#1 Check Assembly Repair Kit, 6" 450STDA used with RK6-450STCK4. Kit Contains Seat Retainer, O-Ring, Seat, Bolt, Poppet Retainer (x4), Handle, Poppet Assembly, Washer (x4), O-Ring, Retainer (x4), Poppet Retainer, Seal Ring, Seat Assembly, and #2 Poppet.