Metal thumbcuffs were once used by the police as a restraint much like handcuffs. Undercover police would carry them on their person. They fit in your pocket and are not as bulky as handcuffs. It just so happens that the two keys included can unlock about 80% of the metal handcuffs found on the market. Check out my comedy thumbcuff routine that I call the FBI Trick. For some reason thumbcuffs are getting harder to find hence the reason I am stocking them here. Buy them before I run out of stock!