I/O MAG XL's oversized spherical shape delivers one of Smith's widest views, and a frame that size usually means extra work to seal against a helmet brim. The Mondo MIPS Helmet's Regulator Climate Control vents close that gap instead, keeping the goggle's larger surface fog-free through the same airflow system that regulates the helmet. What Our Gearhead(R) Experts Are Saying:"I wasn't sure the XL frame would seal clean against the Mondo, but it does, run after run, without a hint of fog creeping in at the edges."