Compatible With: Compatible With Pentair SuperFlo 348021, 348022, 348023, 348024, 348025, 348026, 340036, 340037, 340038, 340039, 340040, 3400341, 341111, 340042, 340043, and 340044 pumps, replaces for 357255 and 357255Z Fit For: Compatible With Pentair Sta-Rite OptiFlo, Sta-Rite SuperMax high pressure pump, Pentair SuperFlo pool and spa pump Effortless Replacement: Our O-ring gasket is easy to install and takes just a few seconds. Make sure to apply PTFE-based lubricant on the gasket before placing it in the pump lid groove, then put back the lid. Precision Leak Prevention - Measures approximately 5.35" ID x 5.77" OD x 0.21" thickness to perfectly seal pump lids, eliminating air suction issues and pressure loss for optimal water flow HIGH-QUALITY REPLACEMENT PARTS: Made of high quality rubber, the product achieves sufficient flexibility to ensure that the product is fit for your filter, with durability, anti-leakage, and long service life Water and Airtight Sealing: The O-ring replacement features a heavy-duty and flexible construction that creates water-tight and airtight sealing, preventing leakage and maintaining the normal functioning of spa and pool pumps .Includes: 5 Pack 357255 Aftermarket Lid O-Rings Fits For Pentair Sta-Rite SuperMax high pressure inground pool and spa pump Fits For Pentair SuperFlo inground pool and spa pump 357255 Lid O-Ring Compatible with Pentair SuperFlo 340036, 340037, 340038, 340039, 340040, 340042, 340043, 340044, 341111, 348021, 348022, 348023, 348024, 348025, 348026, 3400341 It is best to replace O-RING every 3-4 months, depending on the use environment, temperature, water quality pH influence. Maintain pump and filter performance and don't wait for water leakage before doing measures O-Ring Is Made Of Rubber, Replace the Sealing Ring Regularly, the Filter Can Be Sealed For a Long Time and Work Better Please refer to your owner's manual to ensure you are ordering the correct part.