Are well groovy.
They consist of the double bed sized frame but they have two single sized mattresses within them enabling bed partners to choose differing types of mattress- hard, medium, soft etc to suit the individual's taste or requirements This cannot done with the typical English offering.
This also helps immensely when it comes to getting your fair share of the bed as there is clear markation of territory so you don't end up getting just 6" (15 cm, ha!) on one extreme side of the bed as wifey sooooooo graciously allows.
"But I want a cuddle" "Get off, I want to sleep" "Come here" "Git orf" "Hhhuummppfffff"- we've all been there, right?
And you get two single duvets as opposed to one big one- which again is most excellent for keeping some warmth on your side of the six inches.
Aye, Euro beds ROCK!