Wellllll... I've used them for years and I wouldn't be so enthusiastic without further testing. They are only as leakproof as a soda bottle which you re-cap: the threads wear eventually and I find that volatile liquids escape in time. They are very thick, and you won't be able to squeeze out thicker substances (honey, peanut butter, first aid creams or ointments, etc. You can get them out, but will have to scrape the tube to get much out of it. I do find that they are great for sorting, protecting, and organizing small gear. Pills, matches, hooks and split-shot, etc. And I augment the waterproofing by putting waterproof tape over the cap and threads. IMHO they're neat little tubes, but TEST them.