Zero Tolerance is a brand of Kai USA Ltd. The ZT brand first made its appearance in 2006 when we saw a place in the market for a Made-in-USA line of hard-use knives that would meet the needs of professionals in the military and law enforcement, as well as other first responders, such as firefighters and emergency medical personnel.

The brand quickly built a small, but dedicated fanbase, including those who weren’t first responders or military members. Whatever walk of life they came from, ZT owners fell in love with the hard-use designs and premium materials. They called the knives “real beasts” and “proudly overbuilt.”

From 2006 to 2008, ZT created a mix of folding knives and fixed blades, including the military-style 0100, the 0500 M.U.D.D. knife, and the tactical 0610ST.


But it wasn’t until 2009 that ZT created a folder that became a staple of the brand: the 0350. This SpeedSafe® assisted folder was a bit smaller than many of ZT’s larger offerings, but it still had substantial size. Nevertheless, the knife struck a perfect balance and helped reach an untapped audience—those who wanted a beefy folder, but one that was convenient for pocket carry.

This idea carried over into the 2010s. ZT realized that the brand needed to make a transition. While military and first responders were still an important part of the audience, there were many more people who would want a ZT. The team had a mission: show this broader crowd that if you invest in a premium knife, it’s a gamechanger when it comes to form and function. 

And so, ZT pushed the bar.


In 2011, the groundbreaking 0777 was unveiled to the public. This stunning ZT Originals (in-house) design marked the first time ZT utilized its patented Sub-Frame Lock. Combined with a carbon fiber scale, the 0777 feels light in the hand, but it retains the strength of a frame lock knife.

This limited release won BLADE Show’s Overall Knife of the Year. Although not many of them were produced, the knife put ZT on the map. Later, ZT created a more affordable, consumer-friendly version, the 0770CF.

The brand continued turning out award-winning designs, as well as high-end production models. Customers started take notice. ZT wasn’t just about overbuilt tanks anymore. It captured a new audience, those who want sleek, high-performance, everyday carry knives.


With its strong reputation, ZT is known as one of the most trusted premium brands today. No matter what kind of knife user you are, ZT is dedicated to delivering something for everyone.