The Lock Destroyer Card is comprised of "Hooks" and "Shims". The Hook is the larger piece, and the Shim is the smaller, straighter piece.
To secure your lock: Slip the "Hook" portion into a lock. Give it a tug to make sure it won't come out. Simple as that!
To un-secure your lock: insert the "Shim" portion into a lock, and push it towards the tumblers. While pushing the Shim to the tumblers, grip the Hook, and pull both tools out. Easy as that!
*DISCLAIMER: USE WITH CAUTION THIS CAN DAMAGE SOME LOCKS IF NOT USED PROPERLY. The premise of the Lock Blocker is to temporarily restrict or slow down access from somebody using a conventional key. All locks are different and the Lock Blocker does not guarantee full "access denial". You do not need to be an expert lock picker to defeat it. In our experience, most people (the people you want to block from gaining access) do not understand the basics of locks to "defeat" the lock blocker, unless they know what is happening. They will simply use their key to try and get in and find it won't fit and that they cannot remove the lock blocker to gain access. Anybody with basic lock knowledge and a shim, bobby pin, etc. will be able to remove the lock blocker.