The NRS Chaos Full Cut Water Helmet is an excellent choice when you&';re looking for safe, economical and comfortable head protection. Ventilated lower cut covers the ears without interfering with hearing. a This adjustable helmet gives you the features you need and the style you want at a price that won&';t break the bank. a Durable ABS plastic shell dissipates impacts. a Dual-density EVA foam provides outstanding comfort and protection. a Quick-adjust harness lets you customize the fit for total security. a Eight top ventilation ports keep you cool on those hot days. a Three ventilation ports on each side let you hear what&';s going on while the lower side cut protects the ears. a Multiple sizes and quick-adjust harness ensure you&';ll find the right fit. SPECS: Shell Material:- ABS plastic Liner Material:- Dual-density EVA foam Vented:- Yes Adjustment:- Quick-adjust harness Ear Coverage:- Yes Features:- 8 top ventilation ports 3 ventilation ports over the ear on each side Sizing Size Head Circ.(cm) Head Circ. (in) XS 52.5-54 20.7-21.3 S 54-55.5 21.3-21.9 M 55.5-57.5 21.9-22.6 L 57.5-59.5 22.6-23.4 XL 59.5-61.5 23.4-24.2