Bicycle use only, not DOT-approved and not intended for use with motorcycles. LG 22 3/4-23 1/4 58-59. MD 22 1/2-22 3/4 57-58. SM 21 5/8-22 55-56. XS 20 7/8-21 1/4 53-54. A unique fit system combined with Ionic+ anti-microbial fit liner and a Fidlock closure further improves safety and rider comfort.