The giro quarter mtb helmet has an abs shell making it ultra lightweight while the eps liner absorbs impact the internal fit pads not only enable you to get the best fit possible with a range of different thicknesses but are also sweat absorbent great for when you are powering up steep hills at low speed the 8 vents also help to keep you cool and durability is increased thanks to the polyurethane bumper that helps to protect the eps liner this low profile giro mtb helmet co