ATH DFS Helmet by International Riding Helmets (IRH) This popular helmet is covered in rich, durable velveteen, and features a Carbon Fiber front vent strip and rear vents to keep you cool. ASTM F1163-04A/SEI Certified & CE certified to European EN 1384 Standards* * Click on Important Helmet Warning to the right Features: Three-Point Adjustable Retention System IRH"s Dial-Fit System (DFS) ASTM Approved/SEI Certified Item Specifications: Color: Black Sizes: Small (6 3/8 - 61/2) Medium (6 5/8 - 63/4) Large (6 7/8 - 7 1/8)