Fantastically ventilated with 31 inlets, and completely aerodynamic with its removable aero shells, The Bolle One Premium Helmet is also perfectly designed to hold your sunglasses in its Sunglasses Garage if you remove them during the race. With a focus on safety, The One features a Boll exclusive SAFETY QR Code and a specially designed Boll LED. Its Click to Fit System ensures a perfect adjustable fit and its interchangeable winter and summer linings allow for year round use. Complete with a detachable visor for mountain biking, The One offers you everything you need in a cycling helmet. Removable Aero Shells: Allows you to adjust helmet ventilation and aerodynamics. 31 partially or wholly covered inlets gives you real choice in ventilation. Safety QR Code: Allows any person with a smartphone to access your emergency contact info. Rear facing, integrated LED lighting system with continuous or flashing settings helps to maximize visibility and safety. Light is removable for weight and can be replaced with a lighter capsule to fill the space. All Season Helmet: Equipped with two linings one for warm weather, the other for cooler conditions. Attaches easily for quick changes, holds securely. Sunglass Garage: Specific location to hold sunglasses securely on the helmet. Click To Fit System: Easy to use and micro adjustable for guaranteed comfort and perfect, stable fit. Removable Visor: For adventures on and off the road. Sizes: SM 54 58cm, ML 58 62 cm.