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.1 Desert Warfare 04.1000.0123/DW 5.1cm
Fixed blade Knife Extrema Ratio N.K.1 Desert Warfare 5.1cm 04.1000.0123/DW
Extrema Ratio N.K.1 Desert Warfare version. Extrema Ratio N.K.1 Black fixed is a reduced-size knife is based on the skinner and perfected to a true tactical knife. 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.1 is both capable of offense, through very effective slashing strikes, and useful for minute precision work. Total length 129 mm. Blade length 51 mm. Weight 56 g. 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). Available versions: N.K.1 Black, N.K.1 Desert Warfare, N.K.1 Stone washed.
€131.45

In stock

Folding knife Extrema Ratio BD2 R 04.1000.0227/SAT 9.6cm
Folding knife Extrema Ratio BD2 R 9.6cm 04.1000.0227/SAT
Extrema Ratio BD2 R is a medium folder of the BD series. Its handle produced in aluminum makes it light and resistant, also thanks to its steel internal frame. They keep all BD2 characteristics, improved with the new high speed Razor opening system.
€132.26

In stock

Folding knife Extrema Ratio BD1 R 0410000226SAT 7cm
Folding knife Extrema Ratio BD1 R 7cm 0410000226SAT
Extrema Ratio BD1 R is a knife designed for lightness. It is characterized by a very slim profile with a focus on lightness, without renouncing the usual Extrema Ratio toughness and reliability, also thanks to the black anodized, Anticorodal grip. The modified spearpoint, satin blade is made in Bohler N690 steel hardened to 58 HRC, 2.75” (70mm) 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. Scallops milled in the handle help to guarantee a solid grip on the knife and facilitate grip transitions. With an overall length of 6.7” (170 mm) and a weight of just 2.7 oz (75 g) the Extrema Ratio BD1 R is an extremely light and slim knife which makes it an ideal EDC choice.
€129.03

In stock

Tactical knife Extrema Ratio Ermes Satin Ordinanza 0410000443SAT-OR 14cm
Fixed blade Knife Extrema Ratio Ermes Satin Ordinanza 14cm 0410000443SAT-OR
The Extrema Ratio Ermes is a commemorative knife with the satin-finished blade designed by the Special Operations Helicopter Regiment (R.E.O.S.), which is part of the Italian Army Aviation. R.E.O.S. is a helicopter operational unit supporting the special forces, composed of personnel specially equipped and trained to support hostilities in each operational context. The stylized knife guard represents the wings present in the regiment's heraldic symbol. Hybrid Kydex and fabric sheath has a belt attachment with MOLLE system.
€356.45

Shipping after 10-20 business days

Tactical knife Extrema Ratio Ermes Black Operativo 0410000443BLK-OP 14cm
Fixed blade Knife Extrema Ratio Ermes Black Operativo 14cm 0410000443BLK-OP
The Extrema Ratio Ermes is a full-black commemorative knife designed by the Special Operations Helicopter Regiment (R.E.O.S.), which is part of the Italian Army Aviation. R.E.O.S. is a helicopter operational unit supporting the special forces, composed of personnel specially trained and equipped to support hostilities in each operational context. The stylized knife guard represents the wings present in the regiment's heraldic symbol. Hybrid Kydex and fabric sheath has a belt attachment with MOLLE system.
€326.61

Shipping after 10-20 business days

Folding knife Extrema Ratio BD2 Lucky Black 0410000228BLK 9.6cm
Folding knife Extrema Ratio BD2 Lucky Black 9.6cm 0410000228BLK
Extrema Ratio BD2 Lucky is a fully black folding knife with guard. In addition to protecting the users's hands, the guard also acts as a flipper, and the high-speed auxiliary knife opening system makes it easy to use. The BD2 Lucky perfectly combines the functionality of an everyday pocket knife with the elegance of classic Italian style. The streamlined blade is made of Böhler N690 cobalt steel, and the ergonomic handle uses anodized aluminum alloy.
€160.48

In stock

Folding knife Extrema Ratio BD4 Lucky Desert 0410000497DW 12.3cm
Folding knife Extrema Ratio BD4 Lucky Desert 12.3cm 0410000497DW
Extrema Ratio BD4 Lucky is a folding knife with a partial serrated sharpening and a guard, made in a desert color. BD4 Lucky perfectly combines the elegance of classic Italian style and the functionality of a folding knife for every day. The guard also functions as a flipper, and the high-speed auxiliary opening system of the knife makes it easier to use. The ergonomic handle uses anodized aluminum alloy, and the blade is made of Böhler N690 cobalt steel.
€168.55

In stock

Folding knife Extrema Ratio BD4 Lucky Black 04.1000.0497/BLK 12.3cm
Folding knife Extrema Ratio BD4 Lucky Black 12.3cm 04.1000.0497/BLK
Extrema Ratio BD4 Lucky is a folding knife with a guard and a partial serrated sharpening, made entirely in black. The guard also acts as a flipper, and the high-speed auxiliary knife opening system makes it easy to use. The BD4 Lucky perfectly combines the elegance of classic Italian style with the functionality of a EDC folding knife. The streamlined blade is made of Böhler N690 cobalt steel, and the ergonomic handle uses anodized aluminum alloy.
€179.84

In stock

Folding knife Extrema Ratio Panthera Black 0410000135BLK 10cm
Folding knife Extrema Ratio Panthera Black 10cm 0410000135BLK
Extrema Ratio Panthera is a fully black folding knife. This model has absolutely identical characteristics to the T-Razor model, because it is from which Panthera draws inspiration. The difference in this silhouette is that the dorsal part, like in the blades of the Wharncliffe, goes down to the tip of the knife. The Extrema Ratio Panthera features a Razor-called high-speed assisting deployment system, which makes the knife easier to use.
€188.71

In stock

Folding knife Extrema Ratio Panthera Satin 0410000135SAT 10cm
Folding knife Extrema Ratio Panthera Satin 10cm 0410000135SAT
Extrema Ratio Panthera with a satin-finished blade. The model retains all the characteristics of the T-Razor Extrema Ratio model, from which Panthera draws inspiration. The difference in this silhouette is that the dorsal part descends to the tip of the knife, similar to Wharncliffe blades. The Extrema Ratio Panthera features a high-speed assisting deployment system called the Razor, which makes the knife easier to use.
€204.03

In stock

Folding knife Extrema Ratio Resolza 10 Black 04.1000.0168/BLK 10cm
Folding knife Extrema Ratio Resolza 10 Black 10cm 04.1000.0168/BLK
Extrema Ratio Resolza 10 is a folding knife that pays homage to centuries of Italian tradition. The traditional Sardinian resolza is one of the most famous knives in Italy. To this day, it is a constant companion of island farmers and shepherds in their daily work. The knife accompanied them even when people were called to war: in the chronicles of Sassari during the First World War, the knife is mentioned as part of soldiers' equipment. Resolza 10 is an attempt to redefine the traditional silhouette in accordance with the modern Extrema Ratio standards, so as not to overlook the Sardinian craftsmen, who still practice ingrained knife-making techniques and preserve ancient traditions. Resolza 10 retains its original dimensions and proportions, but is manufactured using high quality materials and modern company technologies. The handle has been redesigned, and the blade is more closely approximated to the traditional shape.
€159.68

In stock

Folding karambit knife Extrema Ratio Nightmare Stonewashed 04.1000.0454/SW 7.3cm
Folding knife Extrema Ratio Nightmare Stonewashed 7.3cm 04.1000.0454/SW
Extrema Ratio Nightmare is a karambit folding knife with rescue characteristics. It has been adopted by the special units of U.S.I.V.P. Principality of Monaco Police. Its name comes from the development and consultancy department of Monaco special intervention units. It comes with a standard industrial-grade cutter blade which is easily replaced, a reversable pocket clip, a glass braker placed in the finger ring. It is produced both in black and stone washed version.
€241.94

In stock

Folding knife Extrema Ratio Glauca B1 04.1000.0139/BLK 10.7cm
Folding knife Extrema Ratio Glauca B1 10.7cm 04.1000.0139/BLK
This new folding knife comes out from a cooperation and planning phase with G.I.G.N. (special unit of the French national Gendarmerie). To maximize penetration, a special blade tip has been developed. On the back side of the handle it has a special tool to cut plastic handcuffs. It comes with a rear glass breaker, reversible clip and safety lock. The sheath has a hard ABS structure on a cordura basis and it has several possible ways of fixing: MOLLE system for tactical jackets, belt fixing and side fixing. The sheath is planned to be used with open blade knife.
€459.68

Shipping after 10-20 business days

Neck knife Extrema Ratio N.K.1 Black 04.1000.0123/BLK 5.1cm
Fixed blade Knife Extrema Ratio N.K.1 Black 5.1cm 04.1000.0123/BLK
Extrema Ratio N.K.1 Black fixed is a reduced-size knife is based on the skinner and perfected to a true tactical knife. 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.1 is both capable of offense, through very effective slashing strikes, and useful for minute precision work. Total length 129 mm. Blade length 51 mm. Weight 56 g. 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). Available versions: N.K.1 Black, N.K.1 Desert Warfare, N.K.1 Stone washed.
€128.23

In stock

Survival knife Extrema Ratio Ontos Black No Kit 0410000127BLKNK 16.8cm
Survival knife Extrema Ratio Ontos Black No Kit 16.8cm 0410000127BLKNK
The Extrema Ratio Ontos Black No Kit is a durable knife for tough outdoor tasks. This version does not include a survival kit. The name ONTOS translates from Greek as "phenomenon." Part of the blade's upper surface is serrated. The 168 mm blade is crafted from premium Bohler N690 steel with a special black MIL-C-13924 coating. The durable black Forprene elastomer handle features a lanyard hole. A M.O.L.L.E. system sheath is included. The knife weighs approximately 411 g.
€319.35

In stock

Folding knife Extrema Ratio BF2 CD Black Ruvido 04.1000.0145/RBV 8.7cm
Folding knife Extrema Ratio BF2 CD Black Ruvido 8.7cm 04.1000.0145/RBV
Extrema Ratio BF2 CD Black Ruvido version. BF2's are “Full size” folding knives especially suitable for professional use by military or police operatives on the field. The handle is solid and comfortable, with the reversible clip becoming a useful and comfortable resting point for the thumb in a “reverse” grip. Characteristical lowered flat areas in the handle give access to the opening “pins”, which don’t protrude from the knife when closed. The flat-ground blade is available in a drop-point or a tanto shape, featuring an extra-thick and stout tip (as in model BF1). The renowned LINER-LOCK blade-blocking system is paired with a carter-protected, manually-activated secondary blocking system.
€181.45

Shipping after 10-20 business days

Tactical knife Extrema Ratio Giant Mamba Black 04.1000.0218/BLK 16.3cm
Fixed blade Knife Extrema Ratio Giant Mamba Black 16.3cm 04.1000.0218/BLK
The Giant Mamba has a 6.3 mm thick, 58 HRC Böhler N690 steel, plain edged tanto blade with full length fuller for lightness finished in black or stone washed. The Forprene grip is affixed by a threaded tang that makes the knife sturdy and well balanced. The injection molded, impact grade nylon, M.O.L.L.E. compatible scabbard has a dampening system to avoid blade rattle, twin button safety loop, anti-rotation rubberized thigh strap and a retention safety disengaged by simple pressure on the trigger-like lever. The new knife line minimizes thickness and bulk without skimping on toughness and safety.
€250.81

Shipping after 10-20 business days

Tactical knife Extrema Ratio Contact Desert 04.1000.0215/DW 16.2cm
Fixed blade Knife Extrema Ratio Contact Desert 16.2cm 04.1000.0215/DW
Extrema Ratio Contact Desert version. Contact is a first knife of Extrema Ratio new production line. It has a blade with a lance-shaped profile, a flat grinding and a diamond-shaped geometry. Contact has got a lower guard branch to protect the hand from accidental cuts, upper jumping to improve grip, a concave fuller along the entire length of the blade and a generous thickness blade (6.30mm) All these details make the Contact the elder brother of the now famous Requiem, revisited in proportions and in some technical features. The blade is made in Böhler N690 steel with a hardness of 58 HRC. The sheath is minimalist; most of the fabric has been cut off; it has got a 2nd level retention system, remembering the style of the model it was inspired by.
€226.61

Shipping after 10-20 business days

Tactical knife Extrema Ratio Contact Black
Fixed blade Knife Extrema Ratio Contact Black 16.2cm 04.1000.0215/BLK
Contact is a first knife of Extrema Ratio new production line. It has a blade with a lance-shaped profile, a flat grinding and a diamond-shaped geometry. Contact has got a lower guard branch to protect the hand from accidental cuts, upper jumping to improve grip, a concave fuller along the entire length of the blade and a generous thickness blade (6.30mm) All these details make the Contact the elder brother of the now famous Requiem, revisited in proportions and in some technical features. The blade is made in Böhler N690 steel with a hardness of 58 HRC and a chemical burnishing coating for the Black version. The sheath is minimalist; most of the fabric has been cut off; it has got a 2nd level retention system, remembering the style of the model it was inspired by.
€250.81

Shipping after 10-20 business days

Training knife Extrema Ratio TK BF2 04.1000.0145-TK 8.9cm
Training knife Extrema Ratio TK BF2 8.9cm 04.1000.0145-TK
Training knife Extrema Ratio BF2. Extrema Ratio restyled series of training knives are manufactured in a wide range of models of diverse size and shape. They enable martial arts practitioners and professionals to train different combat techniques with an appropriate and dedicated tool. All training knives are produced in a metallic blue colour which makes them easily identified even when sheathed. The blades are produced from anodized aluminum and have the very same shape and size of the Extrema Ratio standard production models. The handles are the same used in our production models. The sheaths, sold separately, are the same used for the real knives. The stiff blade allows for training complex defensive and disarming techniques. We recommend the use of appropriate protective gear when training.
€32.26

In stock

Survival knife Extrema Ratio Ontos Green No Kit 04.1000.0127/GRN-NK 15.9cm - 1
-6%
Survival knife Extrema Ratio Ontos Green No Kit 15.9cm 04.1000.0127/GRN-NK
Growing demand from the professionals amongst our clients persuaded Extrema Ratio to design a survival tool for all seasons. ONTOS (“the thing” in Greek) is a pure field knife, tough and heavyweight despite its compact size. The serrated segment on the back of the blade is meant as a back-up, never to be caught without a sharp edge ready for use. The MOLLE compatible nylon thigh sheath stays on even in the event of a retreat, when a soldier would drop most of his cumbersome primary equipment. It is possible to buy separately a survival kit to be fixed to knife sheath. Available versions: ONTOS BLACK, ONTOS GREEN.
€300.19
€319.35

In stock

Multi-tool Extrema Ratio TK Tool 2.0 Stonewashed tksw 10cm - 1
Multi-tool Extrema Ratio TK Tool 2.0 Stonewashed 10cm 04.1000.0050/SW
Extrema Ratio 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.
€63.71

Shipping after 10-20 business days

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.