Readyman Lock Blocker Card LOCK BLOCKER - ACCESS DENIAL CSurvival Cards. Dimensions: 3. 5" x 2". Stainless construction. Comprised of eight "hooks" and eight "shims". Can single handedly deny access to 8 locks all in one card! To secure your lock: Slip the "Hook" portion into a lock. Give it a tug to make sure it won't come out. 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.