Rehydrate from any fresh water source with the HydraPak UltraFlask+ Filtration Flask 500ml/17oz. Featuring an integrated filter, this lightweight, collapsible water bottle removes Escherichia coli bacteria, Cryptosporidium parvum cysts, and Giardia lamblia from approximately 1,500 liters of water at a rate of >1L per minute. The high-flow bite valve provides fast hydration, while the 42mm wide opening allows for quick refills. When not in use, the compressible design makes it easy to pack away.