Pentair #2-258 Buna-N O-Ring

The Pentair #2-258 Buna-N O-Ring (Product #: 35505-1440 / 155005) is a factory-original OEM replacement sealing gasket engineered to provide an absolute, leak-proof hydraulic barrier across a broad selection of premium Pentair pool and spa equipment. Designed as a direct-fit sealing solution, this specialized ring is commonly utilized to seal the pump pot strainer lids of high-performance circulation pumps (such as the Sta-Rite® Max-E-Pro® and Max-E-Glas® II series) as well as the outer perimeter of 2-inch multiport backwash valve diverter plates and standard filter bulkhead adapters. Molded from a high-grade, chemical-resistant nitrile rubber (Buna-N) compound, the component delivers exceptional compression memory, superior structural elasticity, and long-term ozone resistance, allowing it to withstand continuous exposure to high chlorine or bromine concentrations, heavy pool mineral scaling, and repetitive mechanical friction without tearing or dry-rotting. When compressed uniformly within its designated seating channel by a hand-tightened lid lock ring or plumbing union collar, this dynamic gasket blocks pressure-side water weeping and prevents catastrophic suction-side air induction that would otherwise cause pump cavitation and a loss of system prime. Built to withstand continuous operating line pressures up to 50 PSI and extreme summer pump pad temperatures, this featherweight part ensures the entire filtration loop operates at peak hydraulic efficiency. The physical weight of this single, lightweight Pentair #2-258 O-Ring is approximately 0.03 pounds (roughly 0.48 ounces, with an nominal inner diameter of 5.98 inches, a cross-section thickness of 0.139 inches, and a packaged shipping weight of approximately 0.05 pounds), providing pool professionals and DIY homeowners with an essential, durable, and highly precise hardware safeguard for flawless water management.