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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Neck knife Extrema Ratio N.K.3 Stone washed 04.1000.0206/SW 7cm
Fixed blade Knife Extrema Ratio N.K.3 Stone washed 7cm 04.1000.0206/SW
N.K.3 is a reduced-size knife that enlargesis the family of neck knives by Extrema Ratio. N.K.3 is bigger than both N.K.1 and N.K.2, featuring a tanto blade 70mm long 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.3 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. Available but not included: BELT-CLIP (for attaching sheath to a belt), polymer UNDER SHIRT SYSTEM (for concealed carry). There are only best fixed blade knives in MyGoodKnife's range.
€130.65

Shipping after 10-20 business days

Tactical knife 434 - Extrema Ratio Fulcrum S Desert Warfare 04.1000.0092-DW 15cm
Fixed blade Knife Extrema Ratio Fulcrum S Desert Warfare 15cm 0410000092DW
Extrema Ratio Fulcrum S Desert Warfare is a shorter version of the famous Fulcrum knife. It has a 15 cm (5.91”) blade. Same qualities of the FULCRUM except for a lighter mass to bring to bear in performing hard work. Weight of Extrema Ratio Fulcrum S Desert Warfare is 304g. 
€301.90

In stock

Dagger Extrema Ratio Nimbus Special Edition
Fixed blade Knife Extrema Ratio Nimbus Special Edition 14.1cm 0410000240SAT-SE
The tactical knife Extrema Ratio Nimbus Special Edition  is a modern version of the Second World War Italian Nimbus assault knife. The Special Edition comes with wooden handle, satin blade, leather sheath and leather special case. The 141mm (5.55") tactical blade is light and compact for ease of use and is made from Böhler N690 steel. The total length of the Nimbus knife is 263 mm (10.35 in). 
This knife celebrates the battle of Case Grizzano which took place on 19th April 1945 between the paratroopers of Nembo and the German 1 Division Fallschirmjäger “Green Devils”, a 12 hours extremely cruel and bloody hand-to-hand blade skirmish.
€606.34

In stock

Folding knife Extrema Ratio BDØ R Black
Folding knife Extrema Ratio BD0 R Black 6cm 0410000459BLKSW
BD0 R Black from Extrema Ratio is a new knife designed for lightness. It is characterized by a very slim profile with a focus on lightness. The blade is made in Bohler N690 steel hardened to 58 HRC, 2.36” (60mm) long, 0.1” (2.5 mm) thick, with a plain sharpening and a faux edge on the first third of the spine. The blade is deployed by the usual “Razor” tang extension which enables effortless ambidextrous operation. A simple yet sturdy liner lock system holds the blade open. The reversible clip with lightening holes contributes to maintain the weight of the knife to a minimum. With an overall length of 5.7” (165 mm) and a weight of just  52 g the Extrema Ratio BD0 R is an extremely light and slim knife which makes it an ideal EDC choice.
€78.23

In stock

Folding knife Extrema Ratio RAO Avio Black
Folding knife Extrema Ratio RAO Avio Black 11.9cm 0410000141BLK G
Extrema Ratio RAO Avio Black is the survival version of RAO knife chosen by the Italian Air Force to complement the equipment package. Blade length is 119 mm. Blade is made of Bohler N690 steel. The improved survival kit includes: whistle, pocket chain saw, water purifying tabs, compass, copper wire, flint and fire striker, LED light, 2.5 mts paracord and diamond-plate sharpener. The sheath holds the knife in open position. The kit is contained in a pocket fastened to the sheath by a MOLLE system.
€401.61

In stock

Tactical knife Extrema Ratio Misericordia Desert
Folding knife Extrema Ratio Frame Rock Titan Black 7.5cm 0410000456BLKTIT
Extrema Ratio Frame Rock Titan Black is a new knife, based on the design of the Ti-Rock, a successful framelock custom made knife that Extrema Ratio has realized for a renowned Italian distributor. Spear point blade 75 mm is made of high quality Bohler N690 steel, with black DLC treatmet finish. The handle is equipped with a pocket clip. Opening the blade is smooth and easy thanks to the bearings. This mechanism allows the user to adjust the force required to release the blade with the screw. Framelock. The knife weighs about 270 g. Made in Italy. It comes with a special ABS case.
€441.93

In stock

Folding knife Extrema Ratio BDØ R Wolf Grey
Folding knife Extrema Ratio BD0 R Wolf Grey 6cm 0410000459WG
Extrema Ratio BD0 R Wolf Grey is a new and elegant knife designed for lightness. With an overall length of 5.7” (165 mm) and a weight of just  52 g the Extrema Ratio BDØ R is an extremely light and slim knife which makes it an ideal EDC choice. It is characterized by a very slim profile with a focus on lightness. The blade is made in Bohler N690 steel hardened to 58 HRC, 2.36” (60mm) long, 0.1” (2.5 mm) thick, with a plain sharpening and a faux edge on the first third of the spine. The blade is deployed by the usual “Razor” tang extension which enables effortless ambidextrous operation. A simple yet sturdy liner lock system holds the blade open. The reversible clip with lightening holes contributes to maintain the weight of the knife to a minimum. 
€79.03

In stock

Folding knife Extrema Ratio BDØ R HCS
Folding knife Extrema Ratio BD0 R HCS 6cm 0410000459HCS
BD0 R HCS from Extrema Ratio is a new knife designed for lightness. It is characterized by a very slim profile with a focus on lightness. The blade is made in Bohler N690 steel hardened to 58 HRC, 2.36” (60mm) long, 0.1” (2.5 mm) thick, with a plain sharpening and a faux edge on the first third of the spine. The blade is deployed by the usual “Razor” tang extension which enables effortless ambidextrous operation. A simple yet sturdy liner lock system holds the blade open. The reversible clip with lightening holes contributes to maintain the weight of the knife to a minimum. With an overall length of 5.7” (165 mm) and a weight of just  52 g the Extrema Ratio BD0 R is an extremely light and slim knife which makes it an ideal EDC choice.
€78.23

In stock

Survival knife Extrema Ratio RAO Desert Warfare
Survival knife Extrema Ratio RAO Desert Warfare 11.9cm 0410000141DW
Tactical folding knife Extrema Ratio RAO Desert Warfare with a blade length of 11.9 cm. In June 2006, the “185° Rgt. Ricognizione e Acquisizione Obiettivi” (Target Acquisition Regiment) airborne “FOLGORE” (185° RAO) entrusted to Extrema Ratio the development of a unique knife fitting the unit’s specific operational duties. This resulted in the RAO: a compact survival & field knife, with a heavy and dependable blade. Its very reliable locking system, assisted by an extra safety device, effectively turns this folder into a fixed blade knife. The opening and closing is to be performed with both hands in order to minimize the risk of self-inflicted injuries, as the blade, because of its weight, is a veritable guillotine. The extra safe device is a steel pin to be hand-screwed through two holes by the guard section of the massive Anticorodal aluminum handle. The sheath can be attached to tactical vests or common belts, being MOLLE system--compliant.
€345.16

In stock

Tactical knife Extrema Ratio Fulcrum
Fixed blade Knife Extrema Ratio Fulcrum E.I. 18cm 0410000082BLK-EI
 Extrema Ratio Fulcrum E.I. has black 18 cm blade  made of Bohler N690 steel. The blade can sustain loads of over 150 kilograms without breaking. The tanto-shaped blade allows for large amounts of work and wear while still retaining a sharp, penetrating edge at its exceedingly sturdy tip. Thanks to its weight and top-heavy balancing, the Fulcrum is also suitable for hard work on the field. 
€299.19

In stock

Tactical knife Extrema Ratio 39-09 Ordinanza COFS
Fixed blade Knife Extrema Ratio 39-09 Ordinanza COFS 19.5cm 0410000339BLK-OR
Extrema Ration 39-09 Ordinanza is the result of a project sponsored by COFS (the inter-force operations command for Italian special forces) and its former Commander-in-chief, Gen. Bertolini. This combat knife 39-09 is a restyling of the Model 1939 “paracadutista assaltatore” (assault paratrooper) knife, a celebrated piece of Italian military history. Small changes which make it a highly effective, dependable dagger. The included hard sheath is designed to be worn at the ankle, in the characteristic fashion of Italian paratroopers. The 39-09 Ordinanza version has Forprene handle, black oxide-coated with COFS logo & motto. It comes in ABS engraved case with an ankle sheath and a parade belt sheath. Weight  338 g (11.9 oz)
€496.39

In stock

Tactical knife Extrema Ratio Pugio Desert Warfare 0410000314DW 11cm
-5%
Fixed blade Knife Extrema Ratio Pugio Desert Warfare 11cm 0410000314DW
Though named after a short and pointed Roman dagger,  Extrema Ratio Pugio Desert Warfare sports a cuttlebone-shaped hilt reminiscent of the longer Caucasian knives. Ir’s a boot dagger, a delf-defense backup weapon excellently suited for concealed carry. The blade is hollow ground, while absence of guard prevents accidental entanglement in close quarters. Includes an easy-locking BELT-CLIP hard sheath, adjustable for carrying the knife vertically, horizontally or obliquely (at a 45° angle).
€251.31
€264.54

In stock

Multi-tool Extrema Ratio TK Tool 2.0 Black tktoolblack 10cm - 1
Multi-tool Extrema Ratio TK Tool 2.0 Black 10cm 0410000050BLK
A multifunctional tool with a basic and essential design, jointly developed with military professionals. It features a special tip useful for adjusting and calibrating firearm optics. The front of a TK TOOL 2.0 can be used as a screwdriver suitable for 8/10 mm screws, or as a prying lever. The central slot in the blade can be used as a shackle key. This tool has also features two holes for a cord or paracord used in assembling a field or camping tent. Overall, a much sought-after tool for a number of outdoor activities. MOLLE system compliant
€65.32

In stock

Tactical knife Extrema Ratio Col Moschin C Desert Warfare
Fixed blade Knife Extrema Ratio Col Moschin C Desert Warfare 11cm 0410000200DW
The great Extrema Ratio Col Moschin C Desert Warfare is a compact version of the Col Moschin. The Col Moschin is made for the 9th Parachute Assault Regiment "Col Moschin" of the Italian special forces. It is a modern interpretation of a dagger that was presented to the Arditi: a military force from history, in whose footsteps the 9th is following. It has a unique, distinctive blade shape. It comes with hard belt sheath and belt-clip. The sheath can be worn vertically, horizontally or obliquely (at a 45° angle).
€224.19

In stock

Tactical knife Extrema Ratio Col Moschin C Black
Fixed blade Knife Extrema Ratio Col Moschin C Black 11cm 0410000200BLK
The tactical knife Extrema Ratio Col Moschin C Black. The blade is 5 cm shorter than that of its bigger brother. The Col Moschin is made for the 9th Parachute Assault Regiment "Col Moschin" of the Italian special forces. It is a modern interpretation of a dagger that was presented to the Arditi: a military force from history, in whose footsteps the 9th is following. It has a unique, distinctive blade shape. It comes with hard belt sheath and belt-clip. The sheath can be worn vertically, horizontally or obliquely (at a 45° angle).
€221.77

Shipping after 10-20 business days

Folding knife Extrema Ratio Frame Rock Titan Blue Satin 04.1000.0456/SAT/BLU 7.5cm
Folding knife Extrema Ratio Frame Rock Titan Blue Satin 7.5cm 04.1000.0456/SAT/BLU
Extrema Ratio Frame Rock Titan Blue is a stylish folder with a blue titanium handle that offers high strength and at the same time a lightweight construction. Spear point blade 75 mm is made of high quality Bohler N690 steel, satin finish. The handle is equipped with a pocket clip. Opening the blade is smooth and easy thanks to the bearings. This mechanism allows the user to adjust the force required to release the blade with the screw. Framelock. The knife weighs about 270 g. Made in Italy.
€466.13

In stock

Folding knife Extrema Ratio BF1 CD Desert warfare
Folding knife Extrema Ratio BF1 CD Desert warfare 6.9cm 0410000143DW
The Extrema Ratio BF1 CD Desert warfare is a folding knife for everyday use: simple, essential and functional. The blade is burnished, with a flat grind and a thick, durable tip. Characteristical lowered flat areas in the handle give access to the opening “pins”, which don’t protrude from the knife when closed. The reversible clip is located on the back of the blade and engulfs its tang – making it discreet to carry. Employs the trustworthy Liner-Lock blade blocking system.
€152.42

In stock

Folding knife Extrema Ratio BF1 CT Desert Warefare 04.1000.0144/DW 6.9cm - 1
Folding knife Extrema Ratio BF1 CT Desert Warefare 6.9cm 04.1000.0144/DW
Extrema Ratio BF1 CT Desert Warefare with tanto blade. BF1 is a folding knife for everyday use: simple, essential and functional. The blade is burnished, with a flat grind and a thick, durable tip. Characteristical lowered flat areas in the handle – also burnished black give access to the opening “pins”, which don’t protrude from the knife when closed. The reversible clip is located on the back of the blade and engulfs its tang – making it discreet to carry. Employs the trustworthy LINER-LOCK blade blocking system. Available versions: BF1 CT BLACK, BF1 CT BLACK ROUGH, BF1 CT DESERT WARFARE, BF1 CD BLACK, BF1 CD BLACK ROUGH, BF1 CD DESERT WARFARE.
€152.41

In stock

Fixed blade Knife Extrema Ratio Satre Stone Washed
Fixed blade Knife Extrema Ratio Satre Stone Washed 7cm 0410000222SW
This Extrema Ratio Satre Stone Washed was designed in collaboration with Daniele Dal Canto, a Master Advanced F.I.S.S.S. instructor (Italian Federation of Sport and Experimental Survival). The Satre is made with heat-treated Böhler N690 steel at 58 HRC. This material was chosen for its resistance to oxidation, for the durability of its edge and especially for its reliability, which has been proven over the years. Given its characteristics, it can be employed in a large variety of activities and fields, including survival and bushcraft, or it can be part of an EDC. It can be worn as a neck knife thanks to its Paracord 550 lanyard. The full-tang skeletonized structure allows the customization of the knife by using the Paracord as an handle cover.
€117.74

In stock

Karambit knife Extrema Ratio K -Talon Stone Washed
Fixed blade Knife Extrema Ratio K-Talon Stone Washed 7cm 0410000224SW
The Extrema Ratio K -Talon Stone Washed is a fixed-blade karambit with a full-tang structure. The curved and hooked blade was inspired by the shape of a talon. It is designed to make clear and deep cuts as well as to hook, seize and/or tear. The ring in the back is built to gain a safe and firm grip in every situation. This way the knife does not slip and it makes it extremely difficult to disarm and point at the user.The very thin Kydex sheath has a quick release system and comes with a paracord that allows it to be worn as a neck knife and to be attached to the M.O.L.L.E. system.
€222.28

In stock

Karambit knife Extrema Ratio K -Talon Dark Stone
Fixed blade Knife Extrema Ratio K-Talon Dark Stone 7cm 0410000224DKS
The Extrema Ratio K-Talon Dark Stone  is a fixed-blade karambit with a full-tang structure. It has a particularly thin shape with a thickness of only 10 mm including sheath and scales. The curved and hooked blade was inspired by the shape of a talon. It is designed to make clear and deep cuts as well as to hook, seize and/or tear. The ring in the back is built to gain a safe and firm grip in every situation. This way the knife does not slip and it makes it extremely difficult to disarm and point at the user.The very thin Kydex sheath has a quick release system and comes with a paracord that allows it to be worn as a neck knife and to be attached to the M.O.L.L.E. system.
€229.40

In stock

Machete Extrema Ratio KS 0410000172BLK 24.3cm
Machete Extrema Ratio KS 24.3cm 0410000172BLK
Made famous by the Gurkha regiments serving under the British crown, the “kukri” is a Nepalese all-purpose blade descended from ancient Greek sickle-shaped swords. It’s ultimately a machete with a top-heavy, forward-positioned cutting edge, which enables it to function as an axe while retaining the versatility of a long blade. Extrema Ratio has developed two such tools, our KS and KH models, blending ancient and modern design concepts. Both employ combination grinds. The razor-like hollow grind closer to the grip yields a fine, sharp edge without compromising the overall thickness of the back of the blade (which needs great sturdiness). The tip portion of the blade is instead flat ground, well-angled to effortlessly penetrate wood and vegetation. While similar tools are usually made from softer steel alloys for elasticity and ease of honing, we were able to achieve adequate elasticity using hard BÖHLER N690 steel, making for a remarkably durable edge.
€346.77

In stock

Folding knife Extrema Ratio T911 04.1000.0164/SW 7.6cm
Folding knife Extrema Ratio T911 7.6cm 04.1000.0164/SW
Extrema Ratio T911 folder is a light, medium sized folding knife, designed for professional use by military operators. It features a Bohler N690 cobalt steel modified spearpoint blade heat treated to 58 HRC for best compromise between toughness, ease of sharpening and edge retention.
The blade is 76 mm (3”) long and 4 mm (0.16”) thick, with a stone washed finish and flat edge, and rotates around a pin that can be adjusted for tension, allowing the user to achieve the desired smoothness while deploying the blade. Once adjusted, a secondary screw locks the pin in position.
The handle is hard anodized Anticorodal aluminum alloy, with a black finish, shaped for ease of transition between reverse and saber grip. The blade deploys from the folded position by the usual thumb stud and is secured by a liner lock with an additional safety system to insure maximum reliability under hard use. The safety lever is red colored for better visibility and engages the safety in its forward position for a more instinctive use.
The handle has an integrated belt cutter with easily available industrial grade cutter blades, tungsten carbide glass breaker, a stainless-steel folding marlin-spike and a flat screwdriver in AISI 420 steel, meant to help in rifle scope adjustment. A clip is fixed at the end of the handle, allowing for a deep, concealed carry position with very little of the knife exposed. The clip can be reversed from left to right side. Overall 194 mm. Weight 145 g. Made in Italy.
€258.87

In stock

Folding knife Extrema Ratio BD2 Lucky Desert 0410000228DW 9.6cm
Folding knife Extrema Ratio BD2 Lucky Desert 9.6cm 0410000228DW
Extrema Ratio BD2 Lucky is a folding knife with a desert-colored handle and guard. The BD2 Lucky perfectly combines the elegance of classic Italian style and the functionality of an EDC knife. The ergonomic handle uses anodized aluminum alloy, and the blade is made of Böhler N690 cobalt steel. The guard also functions as a flipper.
€153.23

In stock

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.