The Grivel Stealth Helmet is hyper-light and hyper-ventilated. The polycarbonate shell is co-moulded on a layer of expanded injected foam that absorbs the impact, with an unbelievable weight of 190 grams! The design provides the best airflow ever made. One size (54-62) that can be regulated to fit once the helmet is on. The adjustment system tucks into the helmet for compact storage in your pack or haul bag.