Fas-Trac III Pivot Ratchet Suspension for superior comfort, adjustability, and range of motion. Non-contact foam liner maximizes air flow and breathability for optimal cooling and hygiene. Tri-vented option for optimal air flow and cooling (Non-vented option for use in electrical applications) Field replaceable 4-point chinstraps with multiple adjustment points for customized fit and comfort. Premium moisture wicking headband with breathable foam and hook and loop attachment for easy field replacement. Patented push-button accessory attachment rail and universal clips for head lamps enables quick installation and removal, with no need for an additional carrier. Low profile design, even with a visor or spectacles attached. Convenient rescue whistle integrated into the chin strap buckle. Matte finish HDPE shell. Compatible with a wide range of H1 attachments including face shields, spectacles and V-Gard ear defenders. EN 12492:2012 Mountaineering equipment. Helmets for mountaineers.