A new replacement for P-26 packs containing larger volume pump. "Old Style Plumbing" means your Softub is from 1997 or before. Please call when ordering if you are not sure. All new packs will have the light button and air control. Note: If this is to replace a Hydromate purchased after 2017, ask about the P-31C Model with threaded connectors as well as Syntex vinyl colors.