Primarily used for drop flaps, but can also be used on single doors.
The right-angle strike screws onto the carcass, and the 3/4" high cylinder fits through a 3/4" hole in the flap and is held in place with a pair of screws through the cylinder backplate.
Recessing the 1 3/8" diameter back allows the lock to be used with material up to 7/8" thick. A nickel-plate collar hides any tear-out on the front face.
Comes with two keys. Requires #4 screws (not included).