See our size charts to learn how to use a second liner to change the fit. Very versatile if you share a helmet, wear your hair two ways or add a head scarf. The Defender features matte Polycarbonate and Advanced ABS Composite outer shell; injection molded shell design; washable quick-dry, moisture wicking, anti-microbial 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. New to the United States, 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 and CE EN standards.