FAST & SAFE FILTRATION: The integrated filter removes Escherichia coli bacteria, Cryptosporidium parvum cysts, and Giardia Lamblia from approximately 1,500 liters of water at a rate of >1L per minute.* TWIST CAP & SOFT HIGH FLOW NOZZLE: Unique drink through cap for easy drinking. Twist to close for leakproof seal. Delivers potable water in a user friendly format that is fast and easy to use. MUCKGUARD DUST COVER: Protects the valve from dirt and outside contamination. Opens and closes with one hand - seals valve when closed. FITS BIKE AND SPORT BOTTLES: 63 mm threaded cap design screws perfectly onto HydraPak Polar, Breakaway and Apex bottles. INCLUDED BACKFLUSH ADAPTER: Plugs into filter valve and threads onto a HydraPak Stow or bottle of clean water for backflushing the filter to restore its flow rate.