This is an all-mechanical lock with a large key and high reliability without electronics. It operates in a unique way, similar to dialing on an old telephone — starting at the start of the dial, turning the dial clockwise to a certain digit, then back to the start, and entering a digit code. This is repeated until the last digit is entered, then the dial is turned counterclockwise from the starting point to unlock.

Top quality of All mechanical combination lock on the show,AusToolGrind Expo.