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Test And Materials

To obtain the development of products with a high level of performance, our prototypes and samples undergo the strictest NATO tests, integrated with other more specific and even stricter tests carried out inside our laboratory.To ensure a real and absolute efficiency, we execute comparative tests with the most representative products from other firms in this sector. The standard tests should point out the product limits following the below criteria:

The Blades

Extrema Ratio uses N690 – 58 HRC Stainless Cobalt Steel in the large majority of its knives because the additional cobalt content adds strength to the blade. Suffice to say that the type of steel used to make Extrema Ratio knives makes them quite unique and very strong. The metal content of that “stainless cobalt steel” has been specifically calculated to provide steel that would hold an edge well without being so brittle that it might fracture easily – or easier than competitor knives. What make the steel unique are the higher levels of chrome and cobalt than normally found in most other steel alloys.

Fixed Blade Handles

With the co-operation of the Facoltà di Scienze Motorie of the University of Perugia Extrema Ratio has developed a special handle called ERMH (Extrema Ratio Multipurpose Handle). The grips are a single piece cut to comfortably fit the user hand to help in maintaining a secure grip even under wet, sweaty or bloody conditions. The use of Mil-spec materials for the handles like Kraton, Forprene and special polymers add extra quality details to the final product.

Folder Knife Handles

The material used is black anodized Anticorodal: a strong non-corrosive aluminium alloy of Swiss origin. Heat treated has a tensile strength of approximately 20 tons per square inch. The alloy is noted for its high strength and toughness, corrosion resistance to water and wearing. Handle components are made of the same material of the blades that is N690 – 58 HRC Stainless Cobalt Steel in order to meet AISI 304 and AISI 303 specifications. The process is done according to the mil-spec MIL-C-13924.All the components are coated in a long-lasting black carbonitride process. Folder handles are manufactured following a proper ergonomic design as used for the fixed blade knives.Most of the folder knives have either a Widia, tungsten-carbide cobalt, or hardened and tempered steel glass breaker tip.

Folder Knife Locking System

Abbiamo sviluppato la ERMH (Extrema Ratio Multipurpose Handle) , in collaborazione con la Facoltà di Scienze Motorie dell’Università di Perugia, Two locking mechanisms are used in the folder knives: the LOCK BACK and LINER LOCK.

The former is a basic functional lock. In practice the lock design positions a stop bar parallel to and in direct line with the blade at the upper back or rear tang of the blade to lock the blade open. As the blade is rotated open, the spring tensioned, center pivoted stop bar tracks around the circular portion of the blade tang until it drops or locks into the notched out tang. This style of locking mechanism requires two hands to safely close the blade although you may still easily open the blade single-handed if desired. The latter is a mechanism that when the blade of the knife is in the opened position, it is held in place by a leaf spring (also called a lock bar) that butts up against the tang of the blade to prevent the blade from closing. To release the lock, the user must press the lock bar back toward the handle side, at which time the blade is allowed to close. In the closed position the lock bar rests alongside the handle and the blade.


All of the sheaths are well-designed for special operations usage. They offer friction and snap retention and allow the knife to be worn low on the thigh or affixed in other ways as well.A lot of attention has been given to the manufacturing process as they are considered the link between the operator and the knife. The heavy duty sheaths are unique and specially designed according to the knife they have to accommodate. The rigid sheath is made of ABS plastic and can be worn mounted on webbing compatible with any PALS/MOLLE system. Some use a TEK-LOK fastener. Some sheaths are composed of two detachable parts: the soft part is made of polyamide bonded with polyethylene while the hard part in ABS plastic welded together with a specialised binary epoxy. The elastic straps and webbing are doubled for durability and are made of Cordura®. The snap fasteners are specifically designed for wet environments and are wear and corrosion resistant. Two ambidextrous quick release systems are used: one manual and one pressure operated. The pressure operated system acts as a safety as well though preventing the knife to be accidentally dislodged. The hard sheath combined with a sleek design makes a safe and effective solution for use in airborne operations. This allows the knife to be carried safely and firmly. Some of the sheaths incorporate a diamond sharpening plate.


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