While working aboard the Space Shuttle or International Space Station, astronauts wear a headset connected to a small communications unit. The headset has an earphone and microphone, and the base unit has switches for transmit/receive and volume. The unit can be held in hand or attached to the astronaut's suit by Velcro. This equipment, like a walkie-talkie, enables the astronauts to talk to one another while in separate parts of the spacecraft. They also use it to communicate with the Mission Control Center in Houston. NASA gave the Museum several "comm sets" used on the Shuttle during the 1980s, including this one issued to astronaut Guy Bluford for the STS-8 mission.