Simply a pad for the tongue jack. they can be purchased in the Airstream store at Jackson Center. BTW this has nothing to do with a wheel on the bottom of the tongue jack since Airstreams don't have tongue jack wheels. The bottom of the jack fits in the groove.
This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.