Clamping Jug Lid

This is a clamping lid for gallon-size juice jugs. I wanted to carbonate my home-brew in something larger than a 12 oz bottle, but smaller than my keg. Throw in some free juice jugs (minus lids) from a generous coworker and you have a mid-scale carbonator. I keep them warm in the basement and chill a jug in the fridge when I have company over.
BTW: I know that a metal screw on lid with a gasket would be a better solution, but I couldn't find the size online or at my local brew supply. The mout