Roof Ventilator Base Adapter Function Adapts 31-3/4 in Round Base to 34 in Square Base Material Steel Overall Width 34 in For Round Base Diameter 31 1/2 in Flange Height 1 3/4 in Compatible Grainger Part Number 5DVN3 5DVN4 Finish Galvanized For Fan Type Upblast Fans Includes (6) Bolts (6) Nuts Metal Material Thickness 1.7 in