Lock and Lock airtight, water tight plastic containers

They have a good reputation. I use one for a first aid kit at home.

They make rectangular ones too, which I find more space efficient. I like them for crush and water resistant, dust proof storage for camera gear and other toys. IMHO, they are little heavy for general packing storage where products like the Aloksak take over.

They are a tad heavy, but I think they may be useful for something with less weight consequence like cycle touring. I wish I could find a stainless steel one that could double as a cookpot too