We use this in our SERE kits and found it to hold up and be more useful than others we tried. The holes are so that you may lace it behind your boot laces or attach it to your clothing or gear in hiding. Simply break if from it mold and it is ready to go. 1/2 x 1” Plastic nylon keys works on all universal handcuffs. Made from a specialty composite for durability and flexibility, this universal handcuff key can be easily hidden just about any place you can think of. When this key is used as intended, personnel CANNOT be restrained with their own handcuffs, whether behind their back or around an object, since the handcuff key is intended to be hidden in multiple locations.