Tubeaxial Companion Flange, For Fan Diameter 16 in, For Fan Type Tubeaxial, Mounting Hole Diameter 3/8 in, Material Steel, Body Diameter 18 1/2 in, Bolt Circle Diameter 17 1/2 in, For Use With 4C660, 4TM81, Includes Predrilled Mounting Holes, Inside Diameter 16 1/4 in, Outside Diameter 18 1/2 in, Overall Width 1 1/2 in, Product Type Companion Flange, 1 Pair