3V Gear 2.0 Liter Top Fill Hydration Bladder for camping, hunting, hiking, running, and sports 2.0 Liter; Metallocene PE high strength & taste free film (BPA, Latex & PVC free) Tough construction for maximum abrasion resistance Anti-microbial bladder interior and drink tube to prevent bacteria and mold Top Fill opening for easy fill and cleaning Patented bite valve on/off twist design