SBT Wear RIng Fits Sea-Doo (or Seadoo) Wear Ring (139.5) with Neoprene Seal SBT's Delrin wear rings are created as a replacement to OEM wear rings for your Seadoo. The Seadoo wear ring aids in stopping speed-robbing cavitation in your worn jet pump. Our SBT Delrin wear rings and liners will restore the tight clearance to your impeller. A Jet Ski or Seadoo wear ring is a sacrificial ring that is installed into the jet pump to provide a minimal clearance for the impeller to build thrust. More specifically, SBT has engineered our replacement Seadoo wear rings for reduced friction using one hundred percent Delrin instead of fiberglass filled plastics. Polyoxymethylene or polyacetal, commonly known as Delrin, is an engineering thermoplastic used in precision parts that require high stiffness, low friction and excellent dimensional stability. The Delrin wear rings have very low water absorption and are chemically resistant because they are acetal based plastics. The SBT wear ring performs better and is more economical, which allows you to replace the wear ring every time you are doing work on the jet pump.