Product review (1 stars): Welcomes most bacteria and worms get into your water supply !!
I bought this but made a HUGE mistake.  I realized only later that 15 microns is like, it filters out football-sized bacteria but lets most of the small critters escape.  Our application was backpacking on Isle Royale, which requires 0.2 microns - 100x better filtering than this straw produces!  This is going into the garbage because it's simply not safe.

Think about it.  The huge first carbon stage of a home reverse osmosis system is either 10 micron or 5 micron, and that's mostly for straining out debris.  This straw can't even match the FIRST stage of  a home reverse osmosis system.

Get a Sawyer PointOne system for $29, it's not for yuppie backpackers but it works like a dream - we were rescued by others on the trail who bought these sawyer filters at incredible prices and were generous with their equipment and time - THANK YOU !!