Speed is addictive. That’s why we’ve focused on aerodynamics in the Profit Aero. Our time machine reverses time.The Profit Aero’s architecture keeps the interior ventilated whilst slicing through the air like an F-15. Although let's be realistic. To run like the wind, you need to feel safe. Which is why we include the Boa® fit system. The most well-known, and also the best restraint system. Intuitive, comfortable and precise. When you onehandedly adjust its magnetic Fidlock® buckle you’ll immediately understand why we have been congratulated by triathlon World Champion, Mario Mola.CharacteristicsProfessional aerodynamic cycling helmet Ideal for shaving seconds off your time for races, time trials or triathlonsFidlock® magnetic buckle and Boa® Fit System for a quick, precise fitHighly compact geometry with a small frontal areaAirflow internal architecture for cooling and better aerodynamic performanceTechnologiesThe Boa® Fit System delivers a connected, fast, customized, and durable fit, purpose-built for performance. Boa’s patented system consists of three integral parts: a micro-adjustable dial, a super-strong lightweight lace, and low friction lace guides and is backed by the Boa Guarantee.Internal helmet design comprised of channels that connect the front and rear openings. The large frontal openings enable large volumes of air to enter. Thanks to the continuity of its internal tunnels, effective air circulation is achieved. Whereby air in contact with the head is constantly renewed, thus transferring excess heat to the rear openings. This provides excellent cooling and superior aerodynamic performance compared to conventional internal structures.The Arrow Head system enables the lateral sliding straps to be adjusted perfectly and also guarantees excellent ergonomics. An innovative system that influences cyclist comfort and safety.Magnetic safety buckle. Automatic fastening, no pinching. Simple one-hand opening, can even be opened with gloves.This product has earned EC certification, meeting the technical and quality criteria set out in the corresponding approval.Size Guide for HelmetsTo establish the ideal size, measure your head's circumference, as indicated in the image.Each helmet specifies the appropriate measurements for each size in centimetres.size S-M: 52 -58 cmsize M-L: 58-62 cm