The see-through design of this special training handcuff allows you to view what is really happening when a handcuff is being locked, unlocked, double-locked, etc. It is a fully functional handcuff that allows a student to see and understand the inner mechanical workings of a handcuff. Both the strengths and weaknesses inherent in all handcuffs become apparent. It is also a useful tool for learning unconventional handcuff opening methods, such as the shim pick. Civilian and military police, special agents and prison guards, among many others, must use handcuffs in the course of their duties. The Clear Cuff helps them remain one step ahead!