The Lazer Genesis is an ever popular road specific cycling helmet which as all the top features & great venting of a pro helmet. With its award winning low compact profile design & the Rollsys fitting system permits an accurate & progressive peripheral sizing adjustment. Rollsys is Lazer's very own award winning fit system: simply control the size & the comfort by turning the wheel on the top of the helmet which will adjust the fit of the helmet symmetrically without any pressure points on the head all with a simple one-handed adjustment.