The Endurance Pro helmet has an adjustable sizing system to fit any head size 53-61. By turning a button the helmet can be adjusted to fit any of these head sizes in an instant.The inner part of the button has a rubberized coating which keeps it soft against the skin.  The size regulator can be adjusted three dimensionally to change length, width and height.   The Air Control System, a one piece anti-allergic inner padding in Coolmax can be removed and is washable. The smooth leather chinstrap is non-allergic and also washable.   here are four clips on the helmet shell in order to fasten any headlamp on the market easily and quickly.   Weight 270g. One size 53-61 Colour White with Carbon detailing.