Zero Tolerance is a brand of Kai USA Ltd. It was born in 2006 with a line of knives manufactured in the USA., that would meet the needs of the military and law enforcement, as well as firefighters and emergency medical personnel. The first products were combat knives, but since then, the line has expanded to include a variety of general purpose and premium knives. From larger and heavier outdoor knives to more lightweight knives for daily use. ZT knives always provide knife owners with superior quality.