Uvex Onyx - Whether through the city or across country - if you ride your bike a lot and often, you need a bike helmet with all-round qualities. The Uvex onyx is light and robust, provides reliable protection and keeps the head pleasantly cool with 17 ventilation openings. For more comfort, the helmet has an integrated mosquito net as well as the 3D IAS 3.0 size adjustment and the monomatic closure that can be operated with one hand.