McMaster 97235K49 18 8 Stainless Steel Slotted Shim, 260 Piece Assortment, Trade Size D (5" × 5") 10034027 Yellow Tether Ready No Bolt Yellow Tether Ready No Bolt Clearance 5 16 in Vertical Standards API 598 and FM Approval Mechanism and Body Design Inline Double Disc Seal Material Buna N Sub Category Iron Spring Material Check Valves Stainless Steel Seal Material Check Valves Buna N Item Double Disc Check Valve Flow Design Single Body Material Valves Cast Iron Full Flow Valves Yes Material of Construction cast iron Max Slip these shims around existing mounting fasteners to precisely align and level components such as pumps They’re also good for leveling machines on uneven surfaces