MaxxAir II Smoke Vent Cover (00-933073) by Maxxair®. The New MaxxAir II has doubled the vent opening compared to Maxxair original vent cover and it includes exclusive easy to open hinged brackets, you simply cannot buy a better vent cover. Exclusive side louvers provide unsurpassed cross ventilation. Aerodynamic shape maximizes vent area and mounts to the same holes as the Maxxair original vent cover. Stainless steel snap lock pins remove for easy access. Hinged brackets provide full access for cleaning and inspection of roof vent seal.