Introduction CPSC approved 10 vent helmet Head Lock adjustable dial retention system for a snug fit Removable visor Rear reflector Use:All Purpose Material:Glue on Size:SM/MD 21-1/4 to 22-3/4″ (54 to 56 cm) or MD/LG 22-3/4 to 24-1/2″ (58 to 62 cm) Color:Black, Blue, Red or White Vents:10 Retention:Head Lock Size Filter:SM/MD