Letter box lock
The term "letterbox lock" is used to describe cam locks that lock the letterbox. The cam lock consists of a housing with a locking cylinder with a locking bolt attached to it, colloquially known as a "lever". By turning the key to the open and closed position, the locking bolt is moved by 90° or 180°. The lock is fixed in the letterbox by means of screws with hexagonal nuts or by means of a clamping spring.