Which type of lock commonly has a knob or latch on both sides of the door?

Which type of lock commonly has a knob or latch on both sides of the door?

• A. Mortise locks
• B. Rim locks
• C. Cylindrical locks
• D. Padlocks

Answer: (A)

Mortise locks are built into a pocket cut into the door edge, so the locking mechanism lives inside the door itself. That design makes it common to have a knob or lever on both sides to operate the latch from either side, and often a separate deadbolt as well. This dual-side hardware setup is less typical for the other types: cylindrical locks usually have a key exterior and a thumb-turn interior, rim locks are mounted on the inner surface with hardware typically confined to that side, and padlocks aren’t door locks at all. So the knob or latch on both sides is a hallmark of mortise locks.

Mortise locks are built into a pocket cut into the door edge, so the locking mechanism lives inside the door itself. That design makes it common to have a knob or lever on both sides to operate the latch from either side, and often a separate deadbolt as well. This dual-side hardware setup is less typical for the other types: cylindrical locks usually have a key exterior and a thumb-turn interior, rim locks are mounted on the inner surface with hardware typically confined to that side, and padlocks aren’t door locks at all. So the knob or latch on both sides is a hallmark of mortise locks.