This hatch closing device, flown on Gemini XII, November 11-15, 1966, allowed the astronaut at the conclusion of an EVA, extravehicular activity or "spacewalk," to pull down the hatch from a sawtooth "gain hold" device on the hatch sill. The astronaut would then use it to assist in holding the hatch closed against the seal pressure just prior to the latching operation. It was stowed in the spacecraft under the right instrument panel in a small orbital utility pouch. Buzz Aldrin used this hatch closing deviced upon returning from his 5 hour, 30 minutes EVA during the Gemini XII mission, the last in the program, in which he set an endurance record and demonstrated that EVA techniques were sufficiently developed to proceed with the Apollo program.

NASA transferred this device to the Smithsonian with the Gemini XII spacecraft in 1968.