Generic Buna-N O-Ring (Square) is a sealing component used to help prevent leaks and maintain proper compression between mating surfaces in compatible pool and spa equipment. Gaskets and O-rings are small parts, but they often determine whether a pump, filter, skimmer, heater, valve, or plumbing connection seals correctly after service. This replacement is useful when the existing seal is flattened, brittle, swollen, cracked, pinched, or missing. Because many seals are close in size, matching the part number, shape, profile, and equipment model is more reliable than estimating by appearance alone. When replacing this item, clean the sealing surfaces, check for cracks or warping in the surrounding parts, and use only the lubricant recommended for the specific material and application.For this specific item, use part number 516664 as the primary reference when checking fitment. The vendor listed for this product is Multiple Manufacturers, and the category is O-Rings, which helps identify the most likely equipment area but should not replace direct comparison with the original part. If the old part is still available, compare connection points, mounting locations, color or finish, molded markings, and any printed service numbers before installing the replacement. Replacement sealing part for compatible pool and spa equipment Helps reduce leaks caused by worn, compressed, or damaged seals Best matched by part number, shape, size, and equipment model Useful during pump, filter, valve, heater, or skimmer maintenance Inspect mating surfaces before installing the new seal
