Shopping Cart  |  Sign In  |  Greek  |  Search:     OK


Tactical Diving Knife
29.8 cm
2 kg

635,00 €

Usually ships within 24 hours


The ULTRAMARINE is the result of four years of research and development, conducted by Extrema Ratio in collaboration with Military Dive Teams of the   Italian Special Forces, Law Enforcement Dive Teams and Civilian Underwater Operation Experts.

Units involved in underwater and amphibian operations use a variety of specialty tools. The main objective of the ULTRAMARINE Project is to substitute these different tools with one versatile utensil capable of performing the multitude of tasks that professionals in the fields are asked to perform in these difficult and challenging operations.

The Primary Functions are

  • Field Operations
  • Underwater Operations
  • Emergency Tool
  • Survival
  • Combat

Note: Functions are prioritized by frequency of use in each sector.

Field Operations

As with any respectable working tool, the mass of the blade has to be heavy enough to efficiently chop branches and shrubs in order to make emergency shelters, camouflage emplacements, stretchers, utensils or sector stakes.

  • The serrations facilitate cutting rope when the blade is dull from wear & tear.
  • The steel tang can be used as a hammer or glass breaking tool.
  • The sharp portion of the blade near the handle can be used for precision cutting & whittling.

Underwater Operations

  • To avoid damaging buoyancy or flotation devices during on-board operations with the exposed metal components of the knife, a flap was incorporated to cover the sheath & knife.
  • The slot in the blade was developed for use as a screw-pin shackle wrench.
  • The retention lanyard allows the user to work on equipment without having to sheath the knife.
  • The handle was designed with a plus sized grip & a special anti-slip material developed by Extrema Ratio to facilitate retention while wearing neoprene gloves.
  • With load positioned on the weakest end of the line cutter the blade withstands a load index of 45 kg (99 lbs). On the blade with screw - pin shackle wrench slot, with load positioned in the center, the blade withstands a load index of 70 kg (154 lbs).

Emergency Tool

  • The sheath is designed to be sleek and hydrodynamic, with a close, tight fit to the body that reduces the possibility of entanglements.
  • The sheath also has a quick-release function that allows the knife to be rapidly drawn by simply pulling on the upper portion of the protective flap.
  • The protective flap uses special anti-wet snap fasteners that are specifically designed for water environments.
  • O-ring and retention system are disabled with a strong pull.
  • In panic or shock situations the user will have access to the knife.
  • The knife is designed with a specialized net & line cutting system for use in entanglement emergencies.
  • The knife is designed with reduced hilt guards to reduce the chance of entanglement and snaring while in use.
  • The design of the handle allows the operator to distinguish the orientation of the blade by feel in low light / no light situations.
  • The pointed tang was developed as a glass break device.


  • Besides being a good camp knife the ULTRAMARINE was designed so the handle could be disassembled, the blade attached to a pole and used as a spear.
  • The blade has been treated with a matt finish to reduce light reflection while operating in hostile environments.
  • The sheath incorporates two sharpening diamond sharpening plates: one for the primary blade and the second for the net cutter.


  • The symmetric dagger shape of the blade and a balance point biased toward the handle make the ULTRAMARINE an excellent fighting knife.
  • The pointed steel tang can be used as a blunt force weapon.

Airborne Operations

  • The hard sheath combined with a sleek design make the ULTRAMARINE a safe and effective solution for use in airborne operations, which eliminates the issues of mid-air entanglements, towed jumpers and operator impalement.

Technical Specifications

  • Weight : 375 g
  • Blade length : 150 mm
  • Total length : 298 mm
  • Blade thickness (main blade) : 6,3 mm
  • Blade steel : N690 X105 CrCoMo 182
  • Handle material : Poliamide
  • Serration on the Blade : Yes
  • Finishing and Coating :-Blade: Burnished