Abstract: A combination lock to be fitted in a door having standard size lock and bolt bores therein. A series of code pins extend through the lock bore and are movable between set and reset positions from both sides of the door to permit rotation of an exterior knob spindle to release the lock. An interior knob may be rotated to release the lock even though locked from the exterior. An adjustment feature selectively adjusts the lock to act as either a single lock or a double lock.