Weatherproof, Airtight; Will withstand submersion, overpressure, underpressure (within reason)
Cache Tubes' Compact Dimensions of 5-1/8 in. long by 1-1/4 in. diameter allow it to fit easily in pockets, backpacks, purses, first aid kits, survival kits, glove compartments, and more.
Impact Resistant, Food-safe PET construction with a capacity of 1.5 fl oz (3 tbsp; 45mL) mean it's ideal for holding spices, water purification tablets, compact fishing kits, fire starting kits, .22 lr ammunition, folded documents, currency, gold dust, medication, and so much more.
These cache tubes weigh just 1.4 oz. when empty, so they add very little weight to your every day carry (EDC) items.
5col Survival Supply Cache Tubes are clear plastic soda bottle preforms (sometimes called baby soda bottles) with caps. These are extremely rugged containers ideal for carrying small items that need to stay dry and uncrushed. They're also popular in the geocache community as a cheap, durable way to cache log sheets. This would be a great way to carry a fire kit, a USB key with your important documents, money, an emergency fishing or snare kit, bait, etc.