Lincy Quality Rim Lock.

Type and Placement: It is a rim lock, meaning it is attached to the interior surface of a door rather than being recessed into the edge of the door. Components: The lock body is black, and it features a brass rim cylinder (the part housing the keyway) typically installed on the exterior side of the door. The image shows multiple metal bolts that extend from the lock body to secure the door. Operation: The lock mechanism is operated by a key, which turns the cylinder and moves the bolt. Usage and Specifications: LINCY locks like this are commonly used as household door locks or supplementary locks for added security. General specifications for similar LINCY models might include a 60mm backset and suitability for door thicknesses between 35-50mm.