Oneal Fury RL II Helmet Descend down the most technical trails like a boss with the The Oneal Fury RL II Helmet. It is a light-weight (950g) full face helmet with a sweat absorbing and removable, washable inner liner. It features many vents and channels that are strategically placed throughout for improved airflow. It comes with a detachable go-pro mount for those thrill seekers that wish to record their gnartacular shred sessions and share them with the world.Features Detachable Go Pro mountLightweight (950g) ABS shellMultiple vents and channels for increased airflowSweat absorbing and removable , washable inner linerHeight adjuster visorO'Neal Fidlock(R) magnetic buckle for easy, single handed fastening and releaseExceeds EN1078 safety standard for bicycle helmets SizeExtra SmallSmallMediumLargeExtra LargeHead Diameter (in)20 1/2-21 1/821 1/4-22 1/822 3/8-23 1/823 1/4-24 3/423 7/8-25 3/4Head Diameter (cm)5456586062