The Bauer IMS 5.0 helmet is built with dual density foam, dual comb crown and integrated ear covers. This helmet is also CSA, HECC certified and the adjustment is possible without tools. Dual-density foam, dual first parting, integrated ear covers, tool-free adjustment, size S fits head circumference 52 - 57 cm, size M fits head circumference 54 - 59 cm, size L fits head circumference 56 - 61 cm