When the double-lock is applied on handcuffs it is not possible to shim - you must first deactivate the double-lock.
This would normally be done using a handcuff key; however some handcuffs use a non-standard key so common universal handcuff keys will not work.
To deactivate the double-lock without a key you insert the hook part of this tool into the key-way and carefully move (sweep) the hook inside to locate the double-lock bar.
The location can very depending on the make/model of the handcuffs. Generally the double-lock bar should be moved back towards the location of the double-lock actuator that was either depressed inwards (small pin) or moved towards the direction of the keyway. Once the double-lock is off you can then shim the handcuffs or 'sweep' the lock using the hook to depress the pawls downwards to release the ratchet arm.
The hook can also be used to open handcuffs that have become inoperative due to foreign objects trapped inside or defective parts that would otherwise block a key.
The spike part of the tool will quickly open many heel and toe locking dogs on padlocks, as well as key-ways on most file cabinet locks and tool chests.
By simply bypassing the pins on a key-way all together, the spike part of the tool can release the locking dog faster than standard picking often can.
We recommend that once you have mastered this tool you then try everyday materials (hair-grips, metal wire etc.) to replicate the function of the tool.