Surface-mount catches 2" deep overall, they have 1/8" of recoil and 1/2" of projection (i.e., push the door in 1/8" and the latch will force it out 1/2").
As the door is closed, the latch automatically locks in position, holding the door magnetically.
A steel washer is used on wood doors and a latch plate on glass (or lucite) doors. All come with chrome-plated steel washers. Latch plates are sold separately.
Latches require #4 round-head screws (not included).