An authentic replica of the altimeter used in aircraft the Altimeter Desk Clock is a fully functioning quartz clock. The clock features a replica (non-functioning) adjustment knob, glass face, and twin pointers and uses one AA battery which is supplied. The quartz movement is a sweep movement with a silent tick. The clock front is metal with a glass face and the housing at the back is polycarbonate. This housing pushes off to reveal the quartz mechanism and to allow for the time to be adjusted. A lovely addition to a desk.