Abstract: A lock assembly including a lock, a key and a rail assembly. The lock includes a lock housing and an actuating housing. The lock housing includes a rear notch, an internal notch that houses a spring and a locking tab, and an aperture that houses a second spring. A vertical track member is mounted to the rear notch and it has a vertical cutout. The actuating housing includes rear, lateral and top walls and a protrusion with a notch. The actuating housing is slidably mounted to the lock housing with a pin. The rail assembly is mounted to racks in stores wherein products for display are mounted thereto. The lock mounts onto the rail assembly by inserting the transversal member of the rail behind the protrusion and pressing the actuating housing against the lock housing until the locking tab engage into the notch.