Size Description S 5056 cm M 5258 cm L 5962 cm PROTONE Lightness and Performance With just 215g of weight Protone has the lowest drag and the fastest heat dissipation coefficients compared to any other ventilated helmet Thanks to several ventilation holes and a thick padding material heat and moisture are dissipated very fast improving comfort and performance without giving up on safety the top area is reinforced with an internal plastic substructure that increases crash protection