Mountain bike helmet suitable for men sizes 53 57 cm 58 63 cm main colour black number of air vents 17 safety features fly net visor with visor size adjustment wheel adjustment system features lower edge reinforcement construction in mold weight 245 g inner material polystyrene eps helmet technologies alpina ceramic shell alpina hi eps alpina custom fit alpina run system ergo alpina edge protect alpina shield protect alpina ergomatic certified en d