When considering your counter custody plan, you might be wondering whether or not handcuffs all use the same key. Although the strict answer is no, the practical answer is yes. At least, if you are in North, Central and South America, that is. The vast majority of handcuffs are based on only a couple legacy designs, and since and given set of handcuffs are temporary and not truly permanent restraints the only modest security increase of specialized keyways creates too great a logistical burden on those who typically employ them, namely law enforcement. Accordingly, handcuffs use a standardized key, and keys intended for double locking handcuffs have a double ended key to fit each lock. This is not to say you won't run into some specialized handcuffs or handcuff like restraints such as thumb cuffs that utilize alternate keys. Certain handcuffs utilize high security cylindrical keys but these are a rare exception. Overwhelmingly, you can buy a standard universal handcuff key and be confident that any handcuffs you are restrained with can be unlocked by it.