This is a strap, keyholder, or charm.
From the manufacturer:
No more fumbling in your pocket for tickets, ID, official Tamiya Mini 4WD event entry cards and the like - this convenient car holder will keep them safe and at hand! It features a safety clip that releases the holder in the event that it gets caught or tugged strongly by something, while the holder itself has a clip fasstener. Best of all, the stylish strap has the famous Tamiya twin star logo emblazoned upon it in white.
- Strap length: 87cm, width: 1cm
- Card holder width: 108mm, height: 117mm
Note: Colors may differ from images shown on this site.