Extrema Ratio Knives

Extrema Ratio Arditi is a modern version of the First World War Italian Arditi assault knife. The black blade 167 mm (6.57 in) is made of Böhler N690 steel. The sturdy black polymer handle provides a comfortable grip. The total length of the Arditi knife is 270 mm (10.62 in) Cordura sheath included. Weighs 224 g. (7.90 oz)

The Extrema Ratio MF1 BC is a tan-colored versatile folding knife with textured blade. Everything said about the MF line is also true for the MF1 model. The MF1 has a built-in screwdriver for adjusting the optics of firearms. The knife is designed specifically for use by law enforcement officers and paramilitary units, but due to its compactness, it is also perfect for everyday use.

MF stands for Medium Folder: a product line positioning itself between the BF (Basic Folder) and the Heavy Folder lines. MF knives employ the LINER-LOCK mechanism and are distinguished for their sturdiness; all are equipped with a glass-breaker. An innovative supplementary screw can be unlocked to enable fine-tuning of the main screw, adjusting opening speed to taste. Hemispheric milling marks on handles make it easier to change from saber-style to reverse grip. Clips are reversible. Model MF0 is “the little one” amongst MF knives – basically a compact version of the MF1. It retains all the characteristics of MF1 but has a downsized handle and shortened blade, similar to our SHRAPNEL “back-up” knife. Available versions: MF0 BLACK, MF0 BLACK RUVIDO, MF0 DESERT WARFARE.

Suppressor training knife. 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.

Everything just said of the MF line is true of model MF1. Its variant, MF1 BC (“Belt Cutter”) features a built-in belt cutter in the handle, designed to accomodate a standard industrial-grade cutter blade which is easily replaced. It also sports a built-in screwdriver for adjusting firearm optics. Available versions: MF1 BLACK, MF1 BLACK RUVIDO, MF1 DESERT WARFARE, MF1 BC BLACK, MF1 BC BLACK RUVIDO, MF1 BC DESERT WARFARE.

BF2 R are folding knives especially suitable for professional use by military or police operatives. They keep all BF2 characteristics, improved with the new high speed Razor opening system. Available versions: BF2 R Classic Tanto BLACK, BF2 R Classic Tanto STONE WASHED, BF2 R Classic Tanto DESERT, BF2 R Classic Drop BLACK, BF2 R Classic Drop STONE WASHED, BF2 R Classic Drop DESERT.

BF0 R CD folding knife with Desert handle. Extrema Ratio is proud to present the new basic folder BF0 R CD. It is a small Basic folders. Its handle produced in technopolymer makes it light and resistant, also thanks to its steel internal frame. BF0 R CD employs the trustworthy LINER-LOCK blade blocking system. It keeps all BF0 characteristics improved with new High Speed Razor Opening System. Available versions: Black, Desert, HCS, Ranger Green, Wolf Grey

BF0 R CD folding knife with Tanger Green handle. HCS Extrema Ratio is proud to present the new basic folder BF0 R CD. It is a small Basic folders. Its handle produced in technopolymer makes it light and resistant, also thanks to its steel internal frame. BF0 R CD employs the trustworthy LINER-LOCK blade blocking system. It keeps all BF0 characteristics improved with new High Speed Razor Opening System. Available versions: Black, Desert, HCS, Ranger Green, Wolf Grey

BF0 R CD folding knife with HCS handle. HCS Extrema Ratio is proud to present the new basic folder BF0 R CD. It is a small Basic folders. Its handle produced in technopolymer makes it light and resistant, also thanks to its steel internal frame. BF0 R CD employs the trustworthy LINER-LOCK blade blocking system. It keeps all BF0 characteristics improved with new High Speed Razor Opening System. Available versions: Black, Desert, HCS, Ranger Green, Wolf Grey

Extrema Ratio is proud to present the new basic folder BF0 R CD. It is a small Basic folders. Its handle produced in technopolymer makes it light and resistant, also thanks to its steel internal frame. BF0 R CD employs the trustworthy LINER-LOCK blade blocking system. It keeps all BF0 characteristics improved with new High Speed Razor Opening System. Available versions: Black, Desert, HCS, Ranger Green, Wolf Grey

Extrema Ratio Double grain sharpener in silicon carbide. It is composed of a rough grain side (180) and a fine grain side (400) to carry out a more performing sharpening. Extrema Ratio Double grain sharpener comes with a cordura sheath

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.

Extrema Ratio black baseball cap with embroidered logo (not printed). One size. 

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.

The common features of the "Basic Folder" series, including the BF1 and BF2, are lightness, simplicity and ease of carry. BF1 e BF2 are utility knives, the BF3 is both a utility and a combat knife. The blade is sharp and piercing, the carry (where legally allowed) is sufficiently comfortable. The “bridge like” clip and a long enough pocket will properly conceal the knife. Slim and essential.

The restyling of a classical, a tribute to a veteran, one of the most distributed and used knives during World War II : MARK 2. It was produced in many versions by historical US knives manufacturers but always following the original specs given by the U.S. NAVY. It is the preferred tool among traditionalists who only trust “battle tested" knives. Throughout the years several manufacturers have tried to restyle this knife with little success. It is in fact the original model which is still favoured in the main catalogues. Extrema Ratio’s aim, in this ambitious project, is to keep the original characteristics while developing only functional changes to increase performance. Cobalt reinforced stainless steel is used for the blade, AISI 303 and AISI 304 are used for the other components. The rounded leather handle has been replaced with a fibre glass reinforced nylon handle. The ergonomics of the original knife has been left intact while all structural parts have been oversized to obtain a sturdy versatile knife. The most important changes have been made to solve the so called “weak spots” of the original version. 1.the possibility to disassemble the knife in the field without the need of tools; 2.the Bowie shape was straightened for easy sharpening; 3.the grooves in the “barrel” shaped handle help to find proper blade direction even in dark conditions; 4.the same grooves improve the grip during twisting movements Other small modifications were to add holes on the back tang to add a lanyard and on the front guard to tie the blade on a pole to be used as a spear. For purely estethical reasons the traditional bloodgroove has been “cowardly” replaced with the typical Extrema Ratio “side groove”. The original knife was perfect and no other modifications were needed. The first available versions will be the classic Extrema Ratio Black and the new Desert Warfare which will come with a special HCS coyote sheath specifically developed for SOF units. The black version comes with standard side sheath which includes automatic retention system, protective flap and is M.O.L.L.E. compatible.

Commissioned and officially adopted in 2002 by the Ninth Rgt. Incursori "Col. Moschin", this model is the quintessence of a pure combat knife. Inspired by daggers with an asymmetric blade and straight but slightly orientated handle used by the Arditi, in whose footsteps the Col Moschin Regiment follows, it has been re-elaborated in a modern form, endowed with a double edged blade, (single for the civilian version), integral guards and a removable E.R.M.H. handle in Forprene. Both grindings are hollow grind razor sharp. The centre of gravity is towards the end of the handle, the point especially sharp, it is light, manageable and intuitive. Each new Incursore receives one, and each new Incursore is trained to use it in the best way.

Commissioned and officially adopted in 2002 by the Ninth Rgt. Incursori "Col. Moschin", this model is the quintessence of a pure combat knife. Inspired by daggers with an asymmetric blade and straight but slightly orientated handle used by the Arditi, in whose footsteps the Col Moschin Regiment follows, it has been re-elaborated in a modern form, endowed with a double edged blade, (single for the civilian version), integral guards and a removable E.R.M.H. handle in Forprene. Both grindings are hollow grind razor sharp. The centre of gravity is towards the end of the handle, the point especially sharp, it is light, manageable and intuitive. Each new Incursore receives one, and each new Incursore is trained to use it in the best way.

Boatswain's knife. Thanks to extremely compact shape typical of BF Extrema Ratio models, the extraction of the knife from the pocket becomes easier and it prevents the tool from entangling, a crucial detail in case of emergency. The blade has a flat grinding which allows symmetrical cutting jobs symmetrical with wider support. On the other hand the tip which is thick and durable thanks to the “tanto” version, allows a greater penetration and a more clean and precise cut.The aluminum handle, has the typical "Tactical" structure, already used in the past on the BF models.It has got a pattern of concentric circles giving the handle an additional grip. This structure enables the rinsing of the handle from salt, or organic material, very important considering its primary use in the naval environment. In the central part of the handle its placed a small slot to allow to lock or unlock small wrenches. In the right part of the handle, in correspondence of the liner lock, a steel plate is placed to give a more solid structure to the slot. The BF2 V comes with just one stone washed finishing to find it easier. The same finishing is proposed for the accessories: •reversible clip applicable on both right or left side of handle. •screw regulation system with 12 positions to control the closing and opening of the blade. •marlin sparkle on the tang of the handle with a length of 70mm to untie knots in ropes or thick cords. In opened position it is fixed by a steel mechanism easy to activate and placed inside the handle in order to feel it while handling the knife. It comes with a plastic lanyard with a fix to be fix to the belt, with a joint to allow the different placements and with a quick release simply pushing of the clip button. The length and flexibility of the lanyard allows to work with the tool in the maximum operating area what a shorter lanyard would not allow

The Caimano Nero is a tactical knife delivered to the G.O.I., Gruppo Operativo Incursori (Operational Raiders Group) of the Italian Navy, and designed by Extrema Ratio, official COMSUBIN supplier. Its name is a reference and a tribute to the heroic Caimani Neri del Piave (Black Caimans of the Piave river), a unit of the Arditi della Regia Marina (Italian Royal Navy), who used to swim across the Piave river to carry out raids on enemy territory during the First World War. It is an automatic knife with a 4 mm asymmetrical spearpoint blade and a partial sharp false edge to improve the coefficient of penetration. The serrated part of the edge allow to cut highly-resistent cables and fabrics without losing its sharpening. It is a medium folder with a robust structure. It is light and balanced thanks to numerous removal processes applied to its highly-thick aluminum handle scales. The pommel, which recalls the shape of the tail/propel section of the Siluro a lenta corsa (S.L.C.), is designed to improve a rapid extraction of the knife from the pocket. The DLC-coated titanium clip can be positioned in three different angles on both sides to allow maximum customization while wearing it. Its shape is designed to conceal the handle sticking out of the pocket. The automatic blade release system guarantees a complete opening even in the event of accidental impacts during the opening rotation. Among its features, it is equipped with an hard-metal glass breaker and a lock, which prevents the blade from dangerously closing by accident.

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.

Extrema Ratio BD2 Contractor is a double-edged semi-serrated 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 Contractor 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.

The Ranger XXV Anniversarium Limited Edition is a manual version of the Caimano Nero N.A. tactical knife, specifically designed for outdoor use with exceptional performance. This limited edition release consists of only 250 copies, adding to its exclusivity. The blade is crafted from durable Böhler N690 steel, ensuring reliability in various outdoor scenarios. The handle of the knife is constructed with two anodized anti-corrosion aluminum plates in a unique Tactical Mud color. The design incorporates an improved grip at the end of the handle for swift retrieval from the pocket. Additionally, a sturdy metal glass breaker is integrated for emergency situations. The DLC-coated titanium clip, adjustable at three different angles on both sides, is designed to minimize the protrusion of the handle when carried in the pocket. The Extrema Ratio Caimano N.A. Ranger XXV Anniversarium Limited Edition comes packaged in an IP67 certified waterproof polypropylene technical case. This case is equipped with a sealed flap, providing weather, dust, and shock resistance. 

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.