Cobra® SnowCountry® Exhaust Vent For Roof Ridge allows heat and moisture to escape and helps resist snow infiltration in harsh winter weather. It provides 18 sq. inches per linear foot (67,720 m2/lm) of net free ventilating area. The unique EasyTear™ Sizing feature allows you to hand-tear product in 3″ (76 mm) increments — no knives necessary and less waste!