These shims are great for both combination padlocks as well as key operated padlocks. They are used by simply inserting the shim next to the lock shank and then rotating the shim which depresses the latch. These shims are thin enough to slip into most padlocks. There are a few that will not accept these shim, but most are fine. You can also use the brass center punch (item number BBT 621) to assist this process. Detailed instructions are included.