SPECS: (S/M): 21-23 in. (M/L): 23- 25 in. Weight: (S/M): 10.4 oz.; (M/L): 11.4 oz. DESIGN & DETAILS: Ultra-durable helmet that provides full coverage and protection on both the sides and back Sleek, cradle fit for all-day comfort Integrated headlamp clips with an elastic keeper to secure your headlight so you can push through the night TECH SPECS: Features a 2-piece ABS shell construction that allows for optimized fit and dual colorways Fuses EPP foam and an EPS foam puck that meets the proposed UIAA increased side and back protection requirements The Captain's vents provide ample breathability when temperatures rise Low-profile suspension system dials in the fit