Pentair 21" Tank O-Ring Cord

The Pentair 21" Tank O-Ring Cord (part number 24850-0008 or 24850-0008Z) is a heavy-duty, large-diameter perimeter sealing gasket designed specifically for the main body split of 21-inch Pentair Sta-Rite System 3 pool and spa filtration systems, including the Modular Media (S7M series), D.E. (S7D series), and Sand (S7S series) configurations. Extruded from a premium, thick-gauge synthetic nitrile rubber (Buna-N) compound, this thick, continuous rope-style seal features an approximate 21-inch inside diameter and a substantial 1/2-inch cross-sectional thickness. Its primary structural role is to layout seamlessly within the dual-groove perimeter interface where the massive upper filter lid joins the lower tank bottom. When compressed by the main exterior tank clamp assembly, it establishes an absolute airtight and watertight pressure boundary that prevents high-velocity water from weeping or spraying out while the filter is operating under continuous system hydraulic pressures up to 50 PSI. Engineered with exceptional shape memory, this resilient elastomer gasket resists flattening under intense mechanical clamp torque and safely tolerates prolonged exposure to outdoor weathering, seasonal temperature shifts, and harsh pool chemistry like chlorine, bromine, and winterizing acid shock treatments. Due to its dense, thick-walled rubber architecture optimized to bridge a wide circumference, this individual container cord ring carries a net product and shipping weight of approximately 0.65 to 0.70 pounds (about 10.4 to 11.2 ounces).