Has anyone come across the 6 pin tubular locks with numbers 1-6 etched around the pins.
They operate using 6 keys and one special key that rotates the center stump. This means that each time the center stump is rotated a different key is required to open the lock.
They are used on fruit machines, id imagine its so that a manager can assign a different key to an employee and control which employee he decided can access the machine.
clever idea but havent got hold of one to dismantle yet