AWE Aerolite Women's Pink Lady Bicycle Helmet - White/Pink, Size 56-58 HELMET SIZE: 55-58cm. A Unisize Adjustment Headlock System At The Rear Of The Helmet Allows You To Make The Helmet The Perfect Fit Yourself. Side Straps Will Increase/Decrease The Size To Your Liking VENTILATION: There Are An Amazing 25 Air Vents for maximum cooling (Including 7 Rear). COMFORT FIT: EPS Foam Lining With Fitting Pads For Maximum Comfort Inside The Helmet. A Padded Chin Strap For Even More Comfort LIGHTWEIGHT: Incredible lightweight material = 265g Approx, Making This Hardly Noticeable Whilst Cycling DUEL SAFETY CERTIFIED: Conforms to Europen CE EN 1078:2012+A1:2012 and the much tougher USA helmet Safety regulations CPSC to ensure maximum safety!