This timer was part of the spacecraft cabin equipment flown on Apollo 11 in July 1969. It is a mechanical timer that can be operated in two modes (6 minutes and 60 minutes). The timer works like a standard kitchen timer, sounding a bell when the selected interval is over.
The timer was transferred from NASA to the Smithsonian along with the contents of Command Module "Columbia" in 1970.
This object is on display in Human Spaceflight at the Steven F. Udvar-Hazy Center in Chantilly, VA.