Attic Roof Ventilator Base Compatible Grainger Part Number 2C528 Compatible Manufacturer Model Number TV06G Finish Galvanized Flashing Size 20 in x 20 in For Fan Type Wind-Driven Turbines Material Galvanized Steel Throat Diameter 6 in Base Type Flat Base Width 16 in For Use With Flat Roof Mounting Base 6 in Galvanized Outlet Diameter 6 in Overall Height 10 in