I have the "First" in my larger kits. I agree that it is the best option. But, its too big for a small EDC kit that is designed for actual daily carry, not to be kept in a nearby car or office. I also posted this inquiry on another forum and the Seychelles filters, straw and bottle, were suggested. Right now I'm leaning towards those. They have a 25% off sale thru the end of November.