Tubeaxial Companion Flange For Fan Diameter 18 in For Fan Type Tubeaxial Mounting Hole Diameter 3/8 in Material Steel Body Diameter 19 7/8 in Bolt Circle Diameter 16 3/4 in For Use With 4C661 4TM82 Includes Predrilled Mounting Holes Inside Diameter 18 1/2 in Outside Diameter 19 7/8 in Overall Width 1 1/2 in Product Type Companion Flange 1 Pair