The Apollo survival rucksack was equipped with a specially designed survival radio to assist the recovery team in locating the astronauts. Several replacement batteries were included.
This black, cylindrical battery was flown on the Apollo 15 mission in July/August, 1971. It was transferred to the Smithsonian in 1978.
This object is on display in Human Spaceflight at the Steven F. Udvar-Hazy Center in Chantilly, VA.