This quick-release pin, also called a "pip pin" or ball-lock pin, is a type of fastener often used in items that spaceflight crews will assemble and disassemble. It is easy to operate, and it connects two objects securely without the need for a tool. Pushing the small plunger at the top retracts two tiny balls embedded near the point, allowing the pin to slide in or out of a pin hole. Releasing the plunger extends the balls to lock the pin into the hole. The pin is typically held between the first two fingers and operated with the thumb. A small wire tether attached to the ring keeps the unfastened pin attached to the equipment without floating away. These pins are crew friendly and quick to use. They are common on items that must be repeatedly set up, used, then dismantled and stowed, such as the exercise treadmill and cycle used on the space shuttle and space station. NASA sent this item and other crew aids and tools to the Museum after the Space Shuttle program ended in 2012.