The COMPX National Mailbox Lock is a high-security lock that is perfect for securing your mailboxes. This lock is made with a steel body and a hardened steel shackle, making it resistant to tampering. The COMPX National Mailbox Lock is also equipped with a key override, making it easy to open even if you don't have the correct key. The COMPX National Mailbox Lock is a high-security lock that is perfect for securing your mailboxes. This lock is made with a steel body and a hardened steel shackle, making it resistant to tampering. The COMPX National Mailbox Lock is also equipped with a key override, making it easy to open even if you don't have the correct key.