External bolt on AC units

Any experience of them? do they work as well as a normal a/c set up?

I mean this sort of thing-

ebay.co.uk/itm/Caravan-Motor … 27dd17a059

Is a 12v application its for, I do a lot of euro hot stuff in the summer & its really uncomfortable without a/c.

Or actually thinking about it, could a small office type 240v unit be used off a directly wired in inverter for cab use hmm, are a lot cheaper.

Office type is going to draw an awful lot of current, inverter will probably cost as much as the unit if you don’t already own a suitable one.