One-piece construction. Male/female connections - no straps necessary. Engineered weather infiltration protectors at each connection. Pre-punched nail holes. Exterior wind baffles. Adjusts from 3/12 to 8/12 pitches. 18 square inches of netfree ventilating area per linear foot. Miami Dade County Approved 16-0510.24. 34 CFM at wind velocity of 3 MPH; 95 CFM at wind velocity of 8 MPH; 181 CFM at wind velocity of 15 MPH.