The Defender Riding Helmet features glossy or matte Polycarbonate and Advanced ABS Composite outer shell; injection molded shell design; washable quick-dry, moisture wicking liner; stainless steel mesh; comfort padded harness with synthetic suede lining, hook & loop adjustment, and Fastex buckle; two side, two front, one back, and two center stripe vents. One K� Helmets boast the perfect synergy between advanced technology and aesthetically pleasing design. With enough features to appeal to those seeking everything a helmet could possibly offer, wrapped in a package that traditionalists can appreciate, One K� has the best of both worlds. Certified to ASTM standards. Helmet Shape Regular/Round � Is shaped for a head which has almost identical front-to-back and side-to-side measurements. Long Oval � Is shaped for a head which is longer front-to-back (from forehead to the back of the skull) than it is side-to-side (ear to ear).