This CamelBak hydration reservoir features a huge access port for easy filling and cleaning. Features: Omega access port is large enough to put your hand inside, making cleaning and filling a simple task. Hydroguard antimicrobial technology embeds an FDA-approved silver ion compound into reservoir film and delivery tubes. This antimicrobial film eliminates up to 99.99% of common bacteria and fungi. Big Bite valve made of medical-grade silicone provides easy access--simply bite and sip. Screw-down cap prevents leakage.