This ultra-light unit provides protection against giardia, cryptosporidium and other organisms of equal size or larger such as ameba, tapeworm eggs, etc.The Coghlans Water Filter is the most versatile and rugged system for providing giardia-free fresh water to outdoor people in pristine areas.The Coghlans Filter has a capacity of up to 50 gallons with a flow rate of 1 quart per minute (depending on the clarity of the water filtered). Filters particles and micro-organisms down to a nominal 1 micron level. Virtually unbreakable Lightweight (6 oz.) Does not affect water taste Has been thoroughly tested for giardia removal Can be used with a straw or pump