I know those tube vaults must be pretty robust, but wouldn't a few paintball tubes do just as good? Don't screw down, but I've never had one "pop" open on me. And I used to get pretty crazy: crawling through brush, waist deep in water (from pastures, so you can guess what the cows were adding to the mix), bouncine off stuff (wore a cup, so I was damn near fearless).

Anway, at 99cents it probably doesn't matter much, but just another option.

They're also good for chilling wasps so you can measure and mark them...