Shell Material: [shell] polycarbonate, [foam] EPS, WaveCel, [lining] Polartec fleece Audio Compatible: yes Audio System Included: no Ventilation: 10 passive vents Fit Adjustment: 360° BOAⓇ Fit System (dial) The Logan WaveCel Helmet packs advanced protection into a sleek and impressively lightweight package, delivering confidence and comfort on the mountain. The WaveCel liner features an interconnected cell system that crumples to absorb impact like a car bumper and slides to divert rotational force like a MIPS layer.