These mailbox locks are made to be a direct replacements for Salsbury vertical door mailboxes. Every once in a while a neighbor in my apartment building loses their mailbox key. These are a perfect way to give them access to their mail again. A metal clip holds them in place. After getting the old lock open it can be replaced quite quickly with one of these brand new locks which comes with 2 new keys and new metal clip for securing to the mailbox door.