Ultralight, low profile helmet with large vents providing superior ventilation for a cooler, more comfortable ride. With a DialFit comfort system and removable and washable headliner with FlipFold shims for personal fit options, the Liberty is a great option for all types of riding disciplines. Key features include: Low profile Durable, lightweight construction Six mesh covered vents DialFit system NEW XS size FlipFold removable washable headliner with Air-Channel technology ASTM/SEI-certified Hat Size and Head Size XSMALL 6 1/4 - 6 1/2 | 19 5/8" - 20 3/8" SMALL 6 5/8 - 7 | 20 3/4" - 22" MEDIUM 7 - 7 1/4 | 22 - 22 3/4" LARGE 7 1/4 - 7 3/8 | 22 3/4" - 23 1/8" XLARGE 7 3/8 - 7 3/4 | 23 1/8" - 24 3/8"