The US Seal Seal Assy [1-1/4" Shaft 1-3/4 Seat OD Buna] is a replacement pump shaft seal from US Seal Manufacturing designed to help prevent water from leaking along the pump shaft in compatible pool and spa pump assemblies. Shaft seals are critical service parts because they protect the motor side of the pump from water intrusion while allowing the impeller and shaft to rotate properly.This seal is intended for pump repair situations where the existing seal is worn, leaking, heat-damaged, or being replaced during a motor, impeller, or wet-end service. The Buna construction noted in the product name should be matched to the pump application, water environment, and original seal requirements before installation. Replacement shaft seal for compatible pool and spa pump assemblies Part number PS-978 helps identify the correct seal during repair work Buna style/designation should be matched to the original seal requirements Helps protect pump motors from water migration through the shaft area Useful for leak repair, pump rebuilding, and preventative wet-end service