4804 THUMB CUFFS
Thumb cuffs are a metal restraining device that lock thumbs in proximity to each other.
Thumb cuffs were originally intended for use by detectives, narcotics officers and off duty policemen, their size allowing them to be carried in the pocket. Most are rigid devices, while some used in Asian countries are chain-linked, like miniature handcuffs.
Thumb cuffs are rarely used due to an increased possibility of injury, most commonly by tight cuffs blocking blood circulation. Handcuffs are usually used instead.
Thumb cuffs may also be used as improvised toe cuffs by locking the big toes in proximity to each other.
Thumb cuffs with double locks have a lock spring which when engaged, usually using the top of the key, stops the thumb cuff from ratcheting tighter and prevents the subject from tightening them, possibly causing injury. Double locks also make picking the locks more difficult.