Abstract: A combination lock or padlock having pushbuttons where the combination of buttons to be pushed to open the lock is mechanically programmable by the user is disclosed. The lock has a case and a locking arm and associated slider, moveable between a locked and unlocked position. A plurality of buttons project from at least one side of the case, and are owner-reversible between two orientations and moveable through holes in the case between first and second positions. In one orientation, movement of the locking means is barred in the first position and permitted in the second position, and in the other orientation movement is permitted in the first position and barred in the second position. The orientation of any button is not being visually ascertainable from outside the case, so the lock owner can program the combination of the lock by selecting the orientation of the respective buttons.