Glovion Adult Men Light up SOS Safety Bike Helmet Luminous Bicycle Helmet with All Round Fiber Optic Light Material: PC+ EPS Foam; Full in mould construction. Size: Universal Adult 56-63CM (20.8-24.8" Inch) Safety LED Red light with SOS ; with 360 degree fibre optic illumination Constant on /Slow Flashing/Quick Flashing 22 functional vents hole design more reasonable, the unique design is exquisite, style fashion, hole design is reasonable, breathable and comfortable, convenient wearing. Wind tunnel, duct design, effectively reduce the wind resistance. 360 degree fiber optic illumination on helmets is an ideal safety feature and will keep you extra safe as they can be seen easily