1. Constructed of plastic shell with soft foam lining.
2. Adjustable strap.
1. Samll(S): inch 24~30, centimeter 61~76.
2. Medium (M): inch 30~36, centimeter 76~91.
3. large (L): inch 36~42, centimeter 91~107.
4. Extra large (XL): inch 42~48, centimeter 107~122.