What is not to love about the Uber Tech Extrema Ratio knives? The designs are both impressively simple and elegant, complete with the top tier of cobalt steel that delivers an aggressive, extremely long-lasting edge. Initially, the feel is somewhat out of the ordinary. However, once you put one in your hand, the odd design makes sense. The new Extrema Ratio Scout carries through an Italian design legacy which combines style and function in well executed simple elegance. The Extrema Ratio Nightmare Karambit folder is a perfect example of how Extrema can take an idea to a different level.
A traditional karambit folder from most manufacturers is a basic folder with a finger hole in the handle. Extrema Ratio incorporated all the latest bleeding edge karambit features, such as blade auto-deployment, and then pushed the design further by adding a glass break/striking pommel, seat belt cutter, and Extrema’s patented liner locking mechanism. Add to that the wicked sharp front top tip and you have a nasty little Nightmare with a 2.89” blade that is still legal to carry in pretty much any city in the U.S.
The concept of an auto-deploying knife is not specifically new, but it has been applied a bit differently for the karambit folders on the market. Much of the karambit folder technique is around a hidden weapon which leans most use in a blade down edge-out reverse knife grip usually with the index finger in the hole in the handle. A guard/tab on the blade catches on the pocket as the knife is pulled from the pocket and the blade is pulled/snapped open. Most people carry a karambit to open as the hand move forward into action, but some owners also rip the knife open to the rear with the pinky in the handle hole, which delivers a standard forward knife grip. I personally like the rearward deployment the best, as the opening is more reliable.
As with any auto-deploying knife, there is a learning curve to figure out how to get the knife to reliably deploy each and every time. This usually involves some type of twist and yank movement. Apparently I have an un-apparent habit of dragging my fourth finger on the blade which—with a partial double edge knife—creates a trail of blood… quickly. Indeed, this Extrema Ratio knife will cut and is a Nightmare if not treated with respect. Once you get into a rhythm, the blade snaps open at every yank from the pocket and is ready to play. The pocket clip is reversible, so users can decide how you want to position and deploy your own Nightmare. I did find that deployment from my Duluth Trading quick dry shorts was a bit slippery, but hey, every knife is a little slick from these amazingly comfortable leisure/work shorts.
I do like the glass break feature and believe it is a top tier addition for folks who like to break windows for fun or scratch car finishes and steering wheels every time they hop in the car, but I personally wish Extrema had left out this skull caving feature. I just poke myself constantly and scratch everything just like I do with my Gen 1 Microtech Ultratech pointy glass breakers. By contrast, the seatbelt/safety cutter is pretty useful. Imagine a situation where you need to cut away some clothing to apply a bandage or tourniquet and all you had was that wicked, cuts-both-ways Nightmare karambit blade. Your patient would not be happy with you. However, with the safety cutter, you can safely zip through clothing, seatbelts, and zip ties without much issue. I use the cutter for trimming zip ties. I still have not figured out how to replace the “replaceable” razor blade or determine where I can get replacements though.
The Extrema Ratio Nightmare karambit also features Extrema’s Ratio’s manual locking mechanism. Like several of the small and mid-sized Extrema folders, the Nightmare features a liner lock. If more security is needed, the manual locking mechanism can be moved over to effectively secure the liner lock similar to CRKT and a a few other manufacturers.
From a defensive perspective, the Extrema Ratio Nightmare is everything the name implies. The knife delivers very aggressive defensive capabilities, great ergonomics, fast deployment, and an extremely durable rugged design. What I love about this knife is how much capability it packs into a very small size that legally can fit into almost any jurisdictional restrictions.
Where most karambits feature a traditional hook bill blade, the Extrema Ratio Nightmare features a curved tanto blade with a double edged tip. This design delivers something unique while also offering a lot of cutting edges. Part of that power and insane cutting ability is the Austrian N690 cobalt-based stainless steel. The steel is similar in performance to the expensive VG-10 but is actually more expensive and is notably wicked crazy sharp and it stays that way thanks to that N690 steel.
The karambit has been “the” defensive knife for a while due to a lot of martial arts trainers over the years backing up the design concept. The karambit is a knife design that is here to stay, but Extrema Ratio has just perfected the design more than I have seen executed in other knife designs. With the exception of the personal preference on the pokey glass breaker, the Nightmare is a highly-refined tactical knife that can deliver a lot in a defensive knife.
The Nightmare Karambit has a liner lock. It also has an additional manual lock that should be used for an extra layer of safety.
Total knife length: mm 196 (7.72 inches)
Length closed: mm 139.70 (5.50 inches)
Blade length: mm 73.50 (2.89 inches)
Weight: 166g (5.85 ounces)
Blade thickness (Widest Part): 3.00mm (.12 inches)
Blade width (Widest Section): 29.72mm (1.17 inches)
Closed knife thickness (Excluding Clip): 13.72mm (.54 inches)
Blade steel: Bohler N690 cobalt stainless steel*
Blade hardness: Rockwell 58 HRC
Grinding: Flat grind
Serrations on blade: Yes
Lock: Liner lock with additional manual lock
Handle material: Anodized anticorodal aluminum alloy **
Belt clip: Yes – reversible side to side
Window breaker: Yes – on finger ring
Have you tried the Extrema Ratio Nightmare Karambit Folder specifically or carry a karambit-style knife in general? Share your answer in the comment section.
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Major Pandemic is an editor at large who loves everything about shooting, hunting, the outdoors, and all those life saving little survival related products. His goal is simple, tell a good story in the form of a truthful review all while having fun. He contributes content to a wide variety of print and digital magazines and newsletters for companies and manufacturers throughout the industry with content exposure to over 2M readers monthly. www.MajorPandemic.com