Uhh ur thinking of the things they have at wally world. They arnt refilable and im pretty sure they dont make them refillable. Just buy a nine ounce or lift waits.
That would be the only reason to even use one of those small tanks, like if it were going on a pump gun. But other than that just get a bigger tank because it wouldn't really last for that many shots and you would keep having to get it filled.
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