Simple any effective cuff key. Useful for officers as a backup handcuff key (for metal cuffs only), training key, undercover agents, special forces & covert operations. Allows secret access to key for escape if detained, unlawfully. Extremely small and hard to detect. Can also be sown into clothing. To assemble rivet attachment; Insert Male Rivet through clothing or button hole and into smooth side of key to lock in snap rivet; pull / twist off key to release for use. Made with Super Tough Resin for repeated key use. Also handy as a back-up key. At just over 3/4” length and 1/2” width, easily fits on a key chain or lanyard if desired. ** HydaKey is only to be used by Law Enforcement, Military or Security Professionals in accordance with all local, state and federal laws or as a tool to counter illegal detainment, for training or as a backup to standard metal handcuff keys. Improper use to evade arrest by civilians is illegal and strongly discouraged. OT Defense nor Milspec Plastic assumes any responsibility for misuse of this product**