Brooks PHW15 Handwheel for Powhatan 1 1/2" Valve - Hose Valve Replacement Part.
Diameter: 3 5/8" Center: 3/8" x 5/8" with round edges of the 5/8" side
Note: See also the PHWN15 Handwheel nut for Powhatan Valve and PSRS15 Rubber Seal (sold separately).