Longbow,<br><br>I had not thought of an unbreakable waterproof and airtight container for Potable Aqua. The tube is anodized aluminum so the reactivity to Iodine vapor should be low. I normally carry a full bottle of Potable Aqua in my Vest pocket, I may get another one of these capsules and try it out with Potable Aqua.<br><br>The Bison Designs web site shows 2 sizes of these capsules. REI only currently has the small version.<br><br>I stuffed my capsule this morning with 4.5 Vaseline cotton balls and added it to my EDC keyring with the BSA HotSpark, Leatherman Micra and a Stainless Steel Pill container.