Bought an 18ltr box a few weeks ago - excellent - takes contents down about 20 degrees below ambient temparature. You will need an inverter too if you want to run it off an EHU.
Les
------------- No matter where you go - there you are!
The cool boxes are set up for 12 volts so if you want them to run from a ehu the you need a MAINS ADAPTOR not a inverter,an inverter is used to convert 12 volts to 240 ie running a laptop from the cigerette lighter.
Purchased the larger one last year. Really excellent buy. A bit more expensive than a lot on the market but well made. We use it in the back of the X-Trail whilst travelling and on 230 volt whilst on site.