Name: Extrema Ratio Ultramarine NEDU diving knife
Brand: Extrema Ratio
SKU: ER04.1000.0321-BLK
Price: 607 EUR
Availability: BackOrder

Work Sharp Professional Precision Adjust WSBCHPAJ-PRO-I sharpening system

notforsale

not_replaced_in

Knivesandtools EDC pouch

KME Precision Knife Sharpening System, Diamond Stone Kit, KF-D4

productlabel

Spyderco Sharpmaker, 204MF

Skerper paddle strop Viking, rough, stropping paddle

Skerper Paddle Strop STP001, stropping paddle

Skerper Basic sharpening set 180/600/1000/3000 with ceramic sharpening steel, SH004

CRKT Veff Sharp Sharpener VEFF1 diamant 600 grit, sharpening steel set

Spyderco - Ceramic File Set

Blade-Tech Tek-Lok (large) universal belt loop mounting system

UltiClip XL clip for sheaths

UltiClip UltiLink Complete Kit, mounting set for sheaths

KNAFS Knife Chart: A Modern Guide to Knives Poster, rolled

UltiClip Slim 2.2 clip for sheaths

Fallkniven Diamond Ceramic Whetstone DC4

Ballistol maintenance oil, 50 ml

Knivesandtools #EveryDayCloth, micro-fibre cloth

Ballistol maintenance oil spray, 200 ml

Knivesandtools 550 paracord type III, colour: black, 100 ft (30.48 m)

Handle/blade: FRN/N690
Blade length: 13,8 cm
Weight: 365 grams


The **Extrema Ratio Ultra Marine NEDU** is a deluxe diving knife, developed in collaboration with military and civil diving teams. This specific model was developed with the people from the Naval Experimental Diving Unit from the United States. They specifically wanted a knife as a tool, not a weapon. That's why this NEDU version doesn't have a sharp tip. It is ideally suited for use underwater and in difficult and challenging conditions.


The main goal of the Ultramarine project was to make several tools obsolete by having one versatile tool. The blade has two cutting edges, one side of which is partially serrated. The mass of the blade is heavy enough to chop effectively. The back can be used as a hammer. 
This knife has a special line cutter. 


 There is a recess in the blade that makes it easy to open oxygen bottles and shackles.


The handle offers an enormous amount of grip. It is made of fibre-reinforced nylon (FRN) and offers unprecedented grip, especially when using neoprene gloves. The shape has also been designed so that it's always easy to determine the position of the knife under poor light conditions.


The design of the holster means it stays tight against the body. A special flap prevents damage to equipment while using the Ultramarine. The knife is always ready for use in a flash. A diamond sharpening stone is stored in the holster.


If you prefer, you can remove the Kydex insert from the nylon sheath and hang it on your belt with one or two Tek-Lok-like clips (included). The Ultramarine also feels right at home on land.



Because a diving knife gets exposed to exceptionally corrosive conditions, the danger of rust is always lurking. Extrema Ratio has opted for an extremely corrosion-resistant steel, namely Böhler N690, but (long-term) exposure to saltwater can always cause extra rust. That's why the blade has a premium coating. As a result, only the edge is at risk of corrosion. For this reason, the knife comes with an eraser that can quickly remove most rust spots. You can sharpen the edge with the supplied diamond sharpener. This is another way to remove rust from the edge.



Naturally, a knife of this quality comes in a good case, so you can store the sheath and all the accessories together.




Extrema Ratio Ultramarine NEDU diving knife

brand

colour

blade_finish

handle_material

knife_edge_type

material_sheath

sharpening_type

knife_bladeshape

sharpening_angle

pocketknife_steel

knife_sheath

value_length

value_weight

value_blade_height

value_blade_length

value_blade_thickness

expectedRestockDate

legal_agecheck_key

msrp_price

engravable

Personalize it! We can engrave many products. Great as a gift! [Read more about the options here](/en/pt/-order-with-engraving.htm). Looking for an engraving? Don't forget to add the product '[Order with engraving](/en/pt/-order-with-engraving.htm)' to your order. 

Can be engraved

warranty

Almost all the products we sell come with a manufacturing warranty. Want to learn more about the warranty? Read our topic: [warranty explained](/en/ct/warranty-explained.htm)

Warranty

origin

The country of origin is the country the product is produced, as far as we know. This may differ from the country where the brand itself is located.

Country of origin

article_number_site

General information

We always measure the blade height at the highest part of the blade.

Blade height

We always measure the blade length ourselves. This is the length of the blade from the tip to the front of the handle. This may deviate from the manufacturer's specification.

Blade length

We always measure the blade thickness at the thickest part of the blade. Often just before the handle. This may deviate from the manufacturer's specification.

Blade thickness

value_handle_length

We always weigh a product as bare as possible. Knives and axes always without their sheath, lights (if possible) without their battery. For knife sets we measure the entire weight. This may deviate from the manufacturer's specifications.

Weight

Dimensions & weight

value_steel_hardness

The hardness in Rockwell C for a knife is always according to the manufacturer's specifications. When a manufacturer specifies a value of 56-58HRC, for instance, we always note the highest value, i.e. 58HRC.

Hardness

Material

fixed_blade_type

knife_best_use

We like to highlight what use the manufacturer had in mind, or what we believe the knife is suited for

Best use

This concerns the type of edge [Want to learn more about a serrated versus a plain edge](/en/ct/pocket-knives-difference-plain-edge-serrated.htm)?

Type of edge

molle_compatible

MOLLE is a mounting system that allows you to attach sheaths and other accessories to backpacks. With this specification we indicate whether a product is already MOLLE-compatible by default. [Want to learn more MOLLE](/en/ct/what-is-molle.htm)?

MOLLE-compatible

We measure the sharpening angle ourselves. This value is the angle per side.  So 20º means that the total angle of the edge is 40º. Please note that knives are almost always sharpened by hand, even in factories. This value is therefore only an indication of a single tool measured by us. You are always free to choose your own sharpening angle. [Learn more about sharpening angles](/en/ct/sharpening-angles-explained.htm).

Sharpening angle

In terms of grind we are talking about how the complete blade thickness extends into the edge. Want to learn more about grinds? [Read all about grinds on knives](/en/ct/knife-grinds.htm).

Extrema Ratio Ultramarine NEDU diving knife

Extrema Ratio Ultramarine NEDU diving knife

Full description

Specifications

Specifications

General information

Dimensions & weight

Material

Features & functions

Scope of delivery

Extrema Ratio Ultramarine NEDU diving knife

Extrema Ratio Ultramarine NEDU diving knife

Extrema Ratio Ultramarine NEDU diving knife

Full description

Specifications

Specifications

General information

Dimensions & weight

Material

Features & functions

Scope of delivery

Extrema Ratio Ultramarine NEDU diving knife

Relevant topics