Stansport 104 Aluminum Storage Capsule - Large

I'm going to use for camping/emergency supplies and for outside storage of a key. These capsules are fairly heavy, seem sturdy, and are probably durable, but these might not be good for lightweight backpacking. I water tested these storage capsules upon receipt. I placed Kim-Wipes tissues in the capsules, hand tightened and placed in a bucket of water for 24 hours. Both the small (green) and medium (silver) capsule were water tight with no leakage into the capsule. However, the tissue in the large (blue) capsule had wet tissue and about 1 teaspoon of water inside the capsule. So I dried out the L capsule, put in new tissue, hand tightened and then further tightened the top and put the capsule in the bucket of water again for 24 hrs. On the second try, the tissue was damp but there was no loose water inside the L capsule even though the top was tightened more that on the first try. It's pretty easy to see that the gasket/O-ring with the L blue capsule is rounder and not as flat as that of the gasket/O-ring that comes with the medium and small capsules (see photos), This rounded gasket probably does not make a complete seal in the L capsule compared to the flatter gaskets in the S and M capsules. If you further tightened the large gasket you might actually deform the gasket to the point that it would leak even worse, but what I found with additional tightening is that I had a hard time opening the capsule as the threading is metal on metal. For my purposes, all the capsules will work, and I like that these capsules come with carabiner so that they can be hung up or clip onto things. In damp or wet environments, the L capsule needs to be treated as if it will not resist water. I would not put any paper or uncoated matches or anything that can rust in this potentially more leaky large capsule. For outside use, I will put the items in a plastic pouch and I plan to use silicone grease to lightly lubricate the threads. As far as key storage, the M and L capsules work for most standard keys and coated head bicycle keys, and the largest blue one will also hold keys with large ends like those on Baldwin keys. However, the emergency key from my car key fob does not fit even in the large blue capsule due to the large size head and length of the key.