Material and installation instructions: 3 packs of an all-metal construction combination padlock, (2 large, 1 xiaoh) the combination is set to 0-0-0. There is an original hole on the back of the padlock, press this hole with a small stick and select your new combination at the same time, you remember this new combination and finally release it and your combination is changed.. Features:This magnetic cam combination lock is erasable, cost effective and secure. Password Security: The 3-digit zinc alloy code allows 1000 possible combinations, harder to crack than 2-digit locks, and cannot be removed by force. Widely used: ideal for lockers such as school and home lockers where there is no need to have a key in your drawer. Design: it is lightweight and easy to carry. Also, there is no key in the lock, so you don't have to worry about losing your lock.