Extrema Ratio

Extrema Ratio is an Italian brand of tactical knives, founded in 1997. The company develops knives for military, police, rescue services, and outdoor use. Extrema Ratio officially supplies knives to the Italian armed forces and security forces, and is ISO 9001 certified and has a NATO supplier code.

You can buy original Extrema Ratio knives at MyGoodKnife—our store is the brand's official dealer. Our selection includes folding tactical knives and fixed-blade knives from popular Extrema Ratio series: Col Moschin, Fulcrum, RAO, Caimano Nero, Dobermann, Selvans, Misericordia, S-THIL, and others.

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Tactical knife Extrema Ratio Misericordia 04.1000.0479/BLK/CIV 11.8cm
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Fixed blade Knife Extrema Ratio Misericordia 11.8cm 04.1000.0479/BLK/CIV
The Extrema Ratio Misericordia is a fixed blade tactical knife that is extremely lightweight and compact. It can be used both as a main knife and as a backup knife. There is a large ring at the end of the handle that allows using martial arts techniques and provides a secure grip. It is equipped with a hard metal skull crusher that can be used also as a glass breaker. Since the knife is designed for professional use, great importance is attached to ease of portability, access and retrieval. The knife is attached to the sheath with a quick release guard that can be easily flipped for left-handed use. Impact resistant nylon sheath is versatile: the adjustable double-clip system allows the user to mount it on different types of belts.
€166.53

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Folding knife Extrema Ratio Ant SP Ranger Stone Washed Green 041000469SWGRN 5.1cm
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Folding knife Extrema Ratio Ant SP Ranger Stone Washed Green 5.1cm 041000469SWGRN
The Extrema Ratio ANT SP is designed to operate in any conditions while remaining undetected. The spearpoint blade, just 5 cm long, is crafted from Bohler N690 steel with a stonewashed finish. The durable, tactical green handle is made of anodized aluminum. Weighing only 44 grams, the Extrema Ratio ANT SP knife features a pocket clip and lanyard hole, making it easy to carry—in your pocket, backpack, or on your gear.
€99.60

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Fixed blade Knife Extrema Ratio Requiem EVO Dark 0410000475MGCBLKBLK 11.6cm
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Fixed blade Knife Extrema Ratio Requiem EVO Dark 11.6cm 0410000475MGCBLKBLK
The REQUIEM EVO DARK is a limited edition knife of just 250 pieces. Its full-tang design adds strength and balance. Black G10 scales with a futuristic CNC design emphasize its modern character. The blade is crafted from Magnacut steel, which combines corrosion resistance, high hardness, sharpness, and resistance to stress. Compact and aggressive in spirit, the REQUIEM EVO DARK is equally at home in gear and in everyday use. The kit includes two sheaths for different scenarios: the Aspis, for concealed everyday carry, quick draw, and comfortable use in the urban environment; and the Kydex, a modular tactical system compatible with MOLLE, Ulticlip, Belt Clip, paracord, and other configurations. Weight: 135g. The knife comes in premium packaging with a numbered metal plate confirming its exclusivity.
€351.39

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Folding knife Extrema Ratio BD4 Contractor Black 04.1000.0498/BLK 12.3cm
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Folding knife Extrema Ratio BD4 Contractor Black 12.3cm 04.1000.0498/BLK
Extrema Ratio BD4 Contractor is a black double-edged semi-serrated folding knife with a guard. The guard also acts as a flipper, and the high-speed auxiliary knife opening system makes it easy to use. The ergonomic handle uses anodized aluminum alloy and the stonewashed streamlined blade is made from Böhler N690 cobalt steel. The BD4 Contractor perfectly combines the elegance of classic Italian style with the functionality of an EDC folding knife.
€196.02

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Folding knife Extrema Ratio MH Stealth 0410000483BLKTM 8.6cm
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Folding knife Extrema Ratio MH Stealth 8.6cm 0410000483BLKTM
Created in partnership with the Kommando Spezialkräfte (KSK) and the Gemeinschaft Deutscher Kommandosoldaten, the MH-STEALTH is a tactical folding knife featuring an inventive design. Böhler N690 steel (58 HRC) with a polished finish and the KSK emblem engraved on it makes up the blade. Its base is serrated, which improves its efficiency while cutting through high-strength materials like ropes or reinforced textiles quickly and precisely.
€273.31

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Folding knife Extrema Ratio Glauca G1 Resque 04.1000.0179SWRED 11.2cm
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Folding knife Extrema Ratio Glauca G1 Rescue 11.2cm 0410000179SWRED
Extrema Ratio GLAUCA G1 RESCUE is specially designed for rescue operations and is intended for a quick and precise response in the most difficult situations. The anodized, anti-corrosion aluminum handle in a bright red color makes the knife visible in all conditions, which is important when there is a need for quick and decisive intervention in emergency situations. The clip, adjustable in two positions, further increases practicality. The blade has a Stone Wash finish and is made of Böhler N690 steel. At the base of the blade there is a saw-tooth section, which makes it especially effective for quick and precise cuts in difficult materials such as ropes and reinforced fabrics, which is ideal for rescue operations.
Another feature of the GLAUCA G1 RESCUE is its folding rescue tool, designed to allow you to quickly make an emergency cut. In addition, it includes a stainless awl (locked in the open position) and a rear glass breaker. The knife is equipped with a LINER-LOCK lock, to which a second, manually operated safety mechanism is added. Every detail of GLAUCA G1 RESCUE is designed to tackle the most difficult challenges decisively and effectively.
€378.49

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Folding knife Extrema Ratio MF1 Evo D Black Satin M390 0410000232M3SATB 9.5cm
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Folding knife Extrema Ratio MF1 Evo D Black Satin M390 9.5cm 0410000232M3SATB
This version of the Extrema ratio MF1 Evo D folding knife has a satin blade made of Bohler M390 steel and a black handle. The handle consists of two anodized aluminum plates. Double-sided steel clip. The LINER-LOCK blade locking mechanism is supported by the new generation "HIDDEN LOCK" safety system. Extrema Ratio MF1 Evo D Black weighs 185 g.
€247.01

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Folding knife Extrema Ratio MF1 Evo D Red Satin M390 0410000232M3SATR 9.5cm
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Folding knife Extrema Ratio MF1 Evo D Red Satin M390 9.5cm 0410000232M3SATR
MF1 Evo is the evolution of Extrema Ratio MF1 knives series. This version of folding knife has a satin blade made ob Bohler M390 steel and red handle. Extrema Ratio MF1 Evo D Red weights 185 g.  The handle is composed of two finely machined anodized aluminum scales. The reversible steel clip allows to conceal the knife inside the pocket, making the knife invisible from the outside. The grip is equipped with a hard metal rear glass-breaker. The blade locking mechanism of the Extrema Ratio MF1 Evo D Re is the LINER-LOCK, supported by a new generation safety system “HIDDEN LOCK”.
€247.01

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Folding knife Extrema Ratio LKU01 Luce 04.1000.0243M3SATC 10cm
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Folding knife Extrema Ratio LKU01 Luce 10cm 04.1000.0243M3SATC
Extrema Ratio LKU01 Luce is a new, limited-edition version (only 100 pieces) of the popular LKU01 EDC knife. The blade features a satin finish and is made of Böhler M390 steel. The handle scales are crafted from carbon fiber, a material known for its high mechanical strength and vibration-absorbing properties, making the grip more comfortable to use. The Extrema Ratio LKU01 Luce weighs 109 g. Its stainless steel pocket clip is removable and ambidextrous. The clip is shaped like a horseshoe, paying tribute to Italian fighters of the 1800s and 1900s who used this symbol. The LKU01 Luce comes in an elegant black box that includes a carbon fiber card signed by master bladesmith Danilo Rossi Lajolo di Cossano. The card has rounded corners, but its lower edge is sharpened, allowing it to be used for defensive purposes if necessary. You are advised to check your local laws to ensure that the use, carrying, and transportation of this tool are permitted in your country.
€310.76

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Tactical knife Extrema Ratio Defender 2 DG Stone washed 0410000489SW 11.8cm
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Fixed blade Knife Extrema Ratio Defender 2 DG Stone washed 11.8cm 0410000489SW
Extrema Ratio Defender 2 DG is the combat version of Scout knife with ultra slim shape. This 118 mm blade comes with a blood drain which makes it lighter. This is DG - double guard version. Defender comes with black kydex sheath fitting the M.O.L.L.E. system.
€188.05

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Tactical knife Extrema Ratio Defender 2 DG Black 0410000489BLK 11.8cm
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Fixed blade Knife Extrema Ratio Defender 2 DG Black 11.8cm 0410000489BLK
Extrema Ratio Black Defender 2 DG is the combat version of Scout knife with ultra slim shape. This 118 mm blade comes with a blood drain which makes it lighter. This is DG - double guard version. Defender comes with black kydex sheath fitting the M.O.L.L.E. system.
€208.76

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Tactical knife Extrema Ratio A.M.F. Black
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Fixed blade Knife Extrema Ratio A.M.F. Black 20.6cm 04.1000.0485BLK
Extrema Ratio A.M.F. (Advanced Multi Function) Black is a 20,6 cm blade knife inspired to a legend in the survival cutlery of the 80es. It can be easily disassembled. Comes with cordura sheath fitting the M.O.L.L.E. system. A survival kit (to be bought only on request) can be easily fixed to the cordura sheath. A.M.F. comes also in desert version.
€335.48

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Tactical knife Extrema Ratio Fulcrum Bayonet Ranger Black
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Fixed blade Knife Extrema Ratio Fulcrum Bayonet Ranger Black 18cm 0410000301RANGER
 Like the original FULCRUM, this Tactical knife Extrema Ratio Fulcrum Bayonet Ranger Black is extremely versatile and strong, capable of sustaining loads of over 150 kilograms. The tanto-shaped blade allows for large amounts of work and wear while still keeping a sharp edge at its exceedingly sturdy tip. This feature, combined with a sharp false edge (in the military versions only), makes the knife retain sufficient combat penetration capability to engage targets covered in heavy clothing, paddings or soft ballistic protections. Thanks to its weight and top-heavy balancing, the FULCRUM BAYONET blade is suitable for hard work on the field.
FULCRUM BAYONET RANGER is the version supplied to the Italian Alpine Paratroopers, with gears and hilt guard for the M4/M16 rifle and wire cutting system, black handle, black rigid sheath, softshell cordura Camo Italia case.
€388.71

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Folding knife Extrema Ratio MF0 T Desert Warfare 0410000148DW 6.8cm
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Folding knife Extrema Ratio MF0 T Desert Warfare 6.8cm 0410000148DW
Extrema Ratio MF0 T Desert Warfare folding knife is equipped with a 7 cm tanto blade.  Extrema Ratio MF0 is a multifunctional folding knife, which is the lightest model in the MF (Medium Folder) line. The knife retains all the characteristics of the MF1, being in fact a smaller version of it. The knife blade is made of Austrian alloy steel Böhler N690 (58 HRC), traditional for Extrema Ratio.
€262.93

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Dagger Extrema Ratio Adra Ordinanza 17 Stormo 17.8cm
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Fixed blade Knife Extrema Ratio Adra Ordinanza 17 Stormo 17.8cm
Extrema Ratio Adra Ordinanza 17 Stormo dagger with black oxide-coated blade 178 mm (7 in) and 17th Stormo logo, serrated partly. 
The “Arditi Distruttori della Regia Aeronautica” (lit. royal air force brave destroyers) were an Italian battalion serving in the North African theater during WW2, and awarded two silver medals of honor.
This ADRA dagger, with its classic European shape, was designed for and with strong input from the commanders and operatives of the 17th. Comes in in ABS engraved case with an ankle sheath and a sand-color parade belt sheath. Total length 311 mm (12.2 in). Weight 331 g (11.7 oz) 
€502.42

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Folding knife Extrema Ratio BD4 Adra Contractor 041000498TM 12.3cm
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Folding knife Extrema Ratio BD4 Adra Contractor 12.3cm 041000498TM
Extrema Ratio BD4 Adra Contactor is available in a limited edition of 70 pieces. It comes inside a certified IP67 waterproof polypropylene technical case with pressurization valve resistant to atmospheric agents, dust and shocks; this includes a scroll outlining the past and present of the 17th Stormo Incursori of the Italian Air Force and a metal plate bearing the progressive number within the limited series.
€276.48

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Folding knife Extrema Ratio T-Razor Black 04.1000.0138/BLK 10cm - 4
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Folding knife Extrema Ratio T-Razor Black 10cm 0410000138BLK
Extrema Ratio T-Razor with black coating. Up to the early 1900s, people commonly carried pocket utility knives. Due to rampant “misuse”, though, laws were passed to the effect that all such knives were to be clipped at the blade-tip, in order to diminish their dangerousness as weapons. Some people then figured they’d get the greatest effectiveness out of the sharp edge of a traditionally flat-point blade shape, and took to carrying straight-razors. Thus, the straight-razor was for a time regarded as a fearsome weapon of self-defense. Such a “misuse” of the common straight-razor inspired our T-RAZOR design. Available versions: T-RAZOR BLACK, T-RAZOR SATIN.
€208.06

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Dagger Extrema Ratio Suppressor Operativo 0410000312BLK 17.6cm
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Fixed blade Knife Extrema Ratio Suppressor Operativo 17.6cm 0410000312BLK
Suppressor Operativo dagger from Extrema Ratio is the memorial dagger, issued to commemorate the thirtieth anniversary of the unit G.I.S., the renowned counter-terrorism unit of the Carabinieri (Italian military police). Black oxide-coated blade 176 mm (6,9 in), without logo, Böhler N690 steel. Side sheath included. Weight 302 g (10.7 oz)
€408.87

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Tactical knife Extrema Ratio Misericordia Desert
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Fixed blade Knife Extrema Ratio Misericordia Desert 11.8cm 0410000479SWD
It is a fixed-blade knife Extrema Ratio Misericordia Desert meant for those circumstances in which a knife has to be extremely light and compact. Extrema Ratio Misericordia Desert preserves all the characteristics of the famous Misericordia, model adopted by the 4th Alpine Paratrooper Regiment, and is derived from the commemorative dagger made for the 140th anniversary of the 4th Alpine Regiment and the 70th anniversary of the institution of the Alpine Paratroopers. The new desert coloration gives to this model a new tone that best meets the needs of the most modern operative units. The blade is milled in Böhler N690 steel, heat treated to 58 HRC, and is 118 mm (4.64”) long and 4mm (0.16”) thick with a flat grind. The knife weights just 87g (3.1oz). The blade has a spear point profile with a full length fuller that makes it even lighter, and a false double edge for ¾ of its length. The finishing is stone washed. The knife has a polymer grip that flows smoothly into the ring, topped by a skull crusher, that allows the use of martial arts techniques and grants a very solid grip on the knife. It has the classic Extrema Ratio groove near the front allowing a better grip and it is secured to the tang by a screw. The knife is secured to the sheath by a fast release safety that can be easily reversed for left hand use. The highly resistant nylon sheath is also in desert and is very versatile; two adjustable loops allow the user to attach it to M.O.L.L.E. systems, allowing fast extraction in a tactical scenario. 
€157.76

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Folding knife Extrema Ratio Glauca G1 04.1000.0179-TM 11.2cm
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Folding knife Extrema Ratio Glauca G1 11.2cm 0410000179-TM
Glauca G1, a new version of the Glauca Exrema Ratio knife, is designed specifically for the famous GSG9 - a unit of the Italian Federal Police. The Glauca G1 knife is officially included in the police arsenal. The handle is made of tactical colored anodized aluminum. The knife is equipped with a glass breaker and a pocket clip that can be installed in different positions. Additionally, the knife is equipped with an awl and a folding rescue tool. Glauca G1 Exrema Ratio has a Liner lock and an additional safety lock. The Drop Point blade is made of Böhler N690 steel with a black finish.
€372.89

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Tactical knife Extrema Ratio Fulcrum Bayonet NFG Desert
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Fixed blade Knife Extrema Ratio Fulcrum Bayonet NFG Desert SW 18cm 0410000310DW
A versatile and extremely tough knife Extrema Ratio Fulcrum Bayonet NFG Desert SW it is a light version of the standard Fulcrum Bayonet. It comes with wire cutter, stone washed blade, desert handle and desert nylon sheath.  This milestone among multipurpose knives, employed on a large scale in Afghanistan as standard issue equipment of the Italian “Nibbio” mission, originated with a COMALP Alpine Troops Command experimental project for renewing trooper equipment. 
€265.32

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Neck knife Extrema Ratio N.K.2 Black 04.1000.0204/BLK 5cm
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Fixed blade Knife Extrema Ratio N.K.2 Black 5cm 04.1000.0204/BLK
N.K.2 is a reduced-size knife that enlargesis the family of neck knives by Extrema Ratio. The main differences from the predecessor N.K.1 are the tanto blade and the blood-draining slot. The design of the handle prevents accidental injury while drawing. A groove on the back of the blade accommodates for the user’s index finger or thumb, according to wielding style. Due to its overall construction, the N.K.2 is both capable of offense, through very effective slashing strikes, and useful for minute precision work. The included, rapid- release Kydex sheath comes with a paracord strip for neck carry. Further, it can be attached via MOLLE system to tactical vests or to any of the compatible cordura sheaths from Extrema Ratio.
€127.42

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Folding knife Extrema Ratio T-Razor Satin 04.1000.0138/SAT 10cm - 1
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Folding knife Extrema Ratio T-Razor Satin 10cm 04.1000.0138/SAT
Extrema Ratio T-Razor folder with satin blade. Up to the early 1900s, people commonly carried pocket utility knives. Due to rampant “misuse”, though, laws were passed to the effect that all such knives were to be clipped at the blade-tip, in order to diminish their dangerousness as weapons. Some people then figured they’d get the greatest effectiveness out of the sharp edge of a traditionally flat-point blade shape, and took to carrying straight-razors. Thus, the straight-razor was for a time regarded as a fearsome weapon of self-defense. Such a “misuse” of the common straight-razor inspired our T-RAZOR design. Available versions: T-RAZOR BLACK, T-RAZOR SATIN.
€212.10

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Tactical knife Extrema Ratio Adra Operativa 0410000313BLK-OP 17.8cm
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Fixed blade Knife Extrema Ratio Adra Operativa 17.8cm 0410000313BLK-OP
The “Arditi Distruttori della Regia Aeronautica” (lit. royal air force brave destroyers) were an Italian battalion serving in the North African theater during WW2, and awarded two silver medals of honor. They were tasked with complex sabotage operations against enemy airfields, which they accomplished employing then unprecedented guerrilla tactics. Now the 17° Stormo Incursori (17th Raiders Wing) of the Italian Air Force picks up their glorious heritage as a special force. As a tangible token of continuity, members of the 17th line up and parade carrying combat daggers at their belts, as the Arditi used to carry. This ADRA dagger, with its classic European shape, was designed for and with strong input from the commanders and operatives of the 17th. Thus begins its road of honor and duty. ADRA OPERATIVA is the black oxide-coated version, no logo, calf sheath included.
€408.87

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Extrema Ratio knives are part of the equipment of many special military units in Italy, as well as police and rescue services. Each model is developed very carefully and undergoes a series of strict tests before being launched into production. The company collaborates with the University of Perugia, where scientists conduct a number of studies, determining the ergonomics of Extrema Ratio products and methods for their improvement. Both Extrema Ratio tactical knives and utility knives are distinguished by impeccable quality. Most knives are made from Austrian N690 steel. Extrema Ratio uses Böhler N690 due to its reliability and predictability. This steel is known for its increased content of molybdenum and cobalt and is characterized by high corrosion resistance. Thanks to this, N690 steel has increased strength and resists impact loads well, which is especially important for tactical use.

Popular Extrema Ratio knife models

The most popular Extrema Ratio knives are Fulcrum, Col Moschin, RAO, Adra. Extrema Ratio also produces several lines of tactical folding knives: BF (basic folder), MF (medium folder), BD4 and BD2 series. Folding models can also be used in urban conditions.

Frequently asked questions about Extrema Ratio knives

What does Extrema Ratio mean?

Extrema Ratio translated from Latin means “extreme measures”. The name reflects the philosophy of the brand: knives are created for situations where maximum reliability, control and readiness for extreme conditions are important.

Where are Extrema Ratio knives made?

Extrema Ratio knives are fully manufactured in Italy. The company is based in the city of Prato and controls the entire process — from development to assembly. The brand is an official supplier for military and law enforcement structures and has NATO supplier certification.

Which Extrema Ratio knife is used by the military?

One of the most well-known models is Col Moschin, developed for the 9th Parachute Assault Regiment of the Italian special forces. Models Fulcrum, Requiem and other knives created for specific unit tasks are also used.

Is it worth buying Extrema Ratio knives?

If you need an extremely strong and reliable knife for tactical tasks, outdoor or intensive use — yes. Extrema Ratio is a tool with a strength reserve, designed for real load. Extrema Ratio knives are also distinguished by the highest assembly quality. Over many years of our store’s operation, this brand has the lowest number of customer complaints regarding product quality.

In the MyGoodKnife online store you can buy original Extrema Ratio knives — we are an official dealer of the brand and offer only authentic products with worldwide shipping.