IIRC.....A number of years ago I remember there was a 'survival straw' that had claimed (EPA level) that it could "purify" water just drinking through it. I also IIRC remember that something like it (maybe the same one) that was quashed because of deceptive / erroneous claims of EPA level purification. My question....

Does anyone know of/have experience with...Are there any 'survival straw' style PURIFIERS? Filters?

Thanks. My searches aren't getting me anywhere.