The X-lite X-501 is the first X-lite composite fibre off-road helmet. Evolution through innovation. Produced in 2 different outer shell sizes for use in high-level competition, the X-lite X-501 displays the customary attention to details which has always distinguished the X-lite br&. With its innovative design & technological features, the X-501 is characterized by its light weight (about 1100 gr for M size), great comfort & effective ventilation system. Ventilation System: Air is directed into the helmet via two frontal air intakes & two other vents positioned in the upper part of the shell, which can be individually operated. Two rear spoilers extract hot air from the inside. Air circulation is further optimized by special ducts located in the helmet inner shell. Lower ventilation is managed by a central air intake, positioned in the chin guard, which facilitates direct air input. There are also two side extractors which assure constant air flow. Removable comfaort padding: A new fully removable & washable liner is manufactured exclusively in UNITHERM, an extremely sophisticated & breathable material in stretch microfibre. UNITHERM is thermoregulating: dry & cool in all weather conditions, thanks to its ability to rapidly disperse body moisture. The structure of the padding is designed to improve air circulation & optimize the ventilation. Removing the liner is quick & easy with a new hook & lock retaining system. composite fibre shell 2 different outer shell sizes head ventilation chin ventilation Double-D chin strap UNITHERM LIGHT microfibre, breathable Removable comfort padding & cheek pads roost deflector 5 years manufacturer guaranty