Source Outdoor WXP Low Profile Hydration System High-performance, low-profile hydration reservoir with wide opening for easy filling, cleaning, draining, and ice insertion Taste-free reservoir with maintenance-free Glass Like liner prevents bio-film build-up Grunge Guard Technology inhibits bacteria growth on the reservoir and drinking tube surfaces Rounded Helix bite valve delivers a full flow with just a soft bite; built-in safety shutoff mechanism Transparent blue co-extruded drinking tube; 2-liter capacity (70 ounces)