Zaosu Racenumber Belt - strap for fastening your race number Convenient and secure fastening option for your race number during your running or triathlon event. Thanks to the elasticated material, the belt adapts perfectly to your body shape and will be barely noticeable during the race. With the ZAOSU Race Belt, thoughts of your race number getting in the way or even coming loose are a thing of the past! Material composition: 100% polyester.