Material: ABS plastic.Size:Diameter 1.7cm/0.67". | A great way to put your number on your clothes without putting any holes in them. | Eliminate the danger of getting hurt by the sharp pin spear.Snap & Lock design is the safest alternative. | With the number buckle, you attach your number bib quickly, easily and accurately on your Sportswear. Easy on, easy off, and can be reusable. | When you need to place a race number, these race number buttons can be used in many sports, such as skiing, skating, track and field, running, dancing.