i've never been in a cat 4 room so i don't know what their coolers look like..
in our cat 3 stateroom it seemed to be one of those tiny refridgerators like in a hotel room wetbar....perhaps it was a cooler...i don't know...but it seemed like a fridge to me...it was under the sink of the wet bar....
and it kept the few drinks that were in there cool....in the cat 3 room there is a small stock of water and soft drinks when you come into the room for the first time...i can't remember if they were in the fridge or on top of the wet bar....
i forgot they were there and ended up not even using them.....