This convenient drink system is perfect for both the Yamaha Storm™ and Lightning™ Mountain Packs. It incorporates the easy on, easy off slide seal which forms a complete seal over the folded reservoir top. Reservoir can be turned inside out for complete cleaning and drying. Constructed of FDA-approved polyurethane, it can be stretched many times its original size. Also features the Plug-and-Play connector, which allows the drink tube to be removed from the reservoir for easier filling and cleaning; a shut-off valve insert keeps liquid in the reservoir.