Half Mortise Locks are a traditional lock style used on 18th, 19th and 20th century furniture. They offer a semi-concealed appearance. The keyhole is all that is seen on furniture exterior. A simple flush plate is seen on interiors of furniture.
Box locks are specifically designed for boxes and chests with lift lids. They can only be used for this type application.
These box locks require a strike plate with hooks. When lid is closed, strike-hooks drop down into lock and are secured by locking mechanism.
If Replacing a Lock: the backset measurement of the lock and the backset measurement on the box itself must match. If the box size differs from what you need, but the backset matches, reworking the mortise may make the lock workable.
Keyhole location measurement is critical. Replacement lock-keyhole-location must match location of keyhole in furniture.
To measure: easiest to measure old lock, if you have it:
Determine desired location of lock