Pentair .139 x 2.109 Large Bulkhead and Elbow O-Ring

The Pentair .139 x 2.109 Large Bulkhead and Elbow O-Ring (part number 190011Z) is a precision-molded sealing component engineered for a wide array of Pentair cartridge and D.E. filtration systems, including the Clean & Clear, Clean & Clear Plus, FNS, FNS Plus, and Quad D.E. series. Fabricated from a premium synthetic nitrile rubber (Buna-N) compound, this heavy-duty circular gasket features a specialized .139-inch cross-sectional thickness and a 2.109-inch internal diameter. Its primary structural role is to seat securely inside the machined seating grooves of the internal plumbing elbows and large bulkhead fittings that penetrate the lower filter tank wall, creating an absolute airtight and watertight compression seal when the retaining nuts are torqued down. By bridging the critical interface between the internal manifold assemblies and the external plumbing lines, it prevents dangerous pressure bypass leaks and keeps the filtration system completely pressurized up to 50 PSI. Built to retain its shape memory and flexibility under constant compression, this durable rubber ring easily resists chemical degradation from chlorinated pool water, acid washes, and fluctuating water temperatures. Due to its streamlined, flexible elastomer composition, this individual O-ring is exceptionally lightweight, carrying a nominal product and shipping weight of approximately 0.02 pounds (about 0.32 ounces).