Internal aerodynamic curved baffles. 18 sq-in of net-free ventilating area per lineal foot. External perpendicular Omni baffles. Weatherproof under-lapping joint. Four drain holes per foot per side. External venturi baffle. Pre-formed to 3/12 pitch. 10 supported nail holes. Alignment tabs. External water shield. Slot width guide lines. Adjusts from 2/12 to 16/12 roof pitches. Co-polymer materials. Limited lifetime warranty, the engineered material assures it will last as long as your shingles. No connectors required. Molded fanfold end plugs, no accessories or alterations needed. Miami Dade County Approved 11-0602.03. 95 cfm at wind velocity of 3 mph, 235 cfm at wind velocity of 8 mph, 430 cfm at wind velocity of 15 mph, OR4 with nails and OR4 with screen available.