
http://www.carcoon.co.uk/Servershield.htm
This company apparently started out making a "cocoon for your car," hence the name Carcoon, but that name brings up other images for me.
Not much real info. It's from Great Britain, so presumably it's looking for 240VAC from mains to maintain its overpressure status. If you use it only for changing film or lenses or for other such uses, you may be able to run it off batteries and inverters. No price.