The Giro Montane Ski Helmet is insanely lightweight and outfitted with a carabineer and our Trip Clip for hooking your lid to your pack, the Montane is up to back country missions and in-bounds operations alike. Progressive Stack Ventilation helps keep goggles fog-free no matter how your day shapes up.Stack Ventilation.Compliance: ASTM F2040-11/CE EN1077.