A new replacement for P-26 and P-31 packs. All new packs will have the light button and air control. 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. Call if you are not sure, or have any questions. You are welcome to call in this order with only a $500 deposit and pay the balance later. Please allow 4 to 6 weeks for delivery.