Source Outdoor Widepac Hydration System Reservoir with Helix Bite Valve Widepac Closure The original user-friendly Widepac Slide Closure opens wide, allows easy filling, cleaning, draining, and ice insertion. Airtight seal. Most SOURCE Hydration Systems and Hydration Packs feature reservoirs with our signature Widepac Closure Taste-Free System - Our co-extruded PE film retains the pure taste with absolutely no plastic flavor, also over time. (BPA and Phthalate free.) GrungeGuard Technology - Our GrungeGuard Technology inhibits bacteria growth on the reservoir and drinking tube for the life of the system. Technology utilizes FDA-approved and EPA-registered anti-microbial agent Glass-Like Technology - SOURCE's Glass-Like Film is 2000% smoother than standard TPU films, with virtually no difference from glass itself, it prevents bio-film build up, making the system virtually self-cleaning Easy Care & Low Maintenance - Simply refill with water and drink again and again without special care. Water will remain fresh for days and even weeks