Adult Equestrian Riding helmet. Vertically anchored retention system for a secure fit, fully adjustable dial allows for a custom and secure fit with the turn of the dial. Removable cushioned head liner for easy care. Multiple mesh covered vents to keep out dirt and debris while allowing maximum air flow. Adjustable nylon harness with quick release snap buckle. Fits sizes 20 1/4"- 21 7/8" ( 6 1/2-7 ) SEI certified to ASTM-F-1163-04a.