HMK (HM4HYDR Hydrapak Reservoir - SHAPE-SHIFT 3 L (100 oz.) Capacity Shape-Shift 3L Reservoir - lock baffle for slim profile, unlock for volume Compatible with all HMK packs Slide-Seal Top - opens wide and seals tight Blaster Valve - silcone, high flow bite-valve with twist shut off 100% BPA and PVC Free Plug-N-Play Connector - quick disconnect for convenient tube removal Quantum Clip - magnetic tube fastener set Reversible and anti-microbial to prevent bacteria & mold Durable, built for a lifetime of tough use, No-Leak Lifetime Guarantee