Yuil Model M-03 stainless steel solid bar handcuffs. Made in Korea and used by Korean police. Steel loop pushes in and pulls out to attach to leg irons or to attach a gang chain or lead chain. Capable of providing the security and restraint of an ordinary handcuff along with the power and control that comes from its solid bar design. Yuil locks are very difficult to pick or shim. The teeth on the jaw are split down the middle into 2 rows to prevent shimming. The locks use double bit (see close-up of key) nonstandard keys that make picking them a real challenge. The keys are not compatible with standard handcuff locks. 2 special keys included. 13.2 ounces.