Among the items issued to astronauts are velcro-backed leather name tags that can be attached to flight suits and jackets. This name tag is a spare for astronaut Thomas K. ("Ken" or "T.K.") Mattingly. He commanded two Space Shuttle missions in 1982 (STS-4) and 1985 (STS-51C). Earlier he was command module pilot on the Apollo 16 mission (1972).
NASA transferred a number of spare astronaut name tags to the Museum over the years, including this one in 2000.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.