because there are no springs.Just the mattress, bought this separately:
http://www.paulsimon.co.uk/Vienna-Double-Storage-Bed-4-6--p3267.html
Had it for 5 months, best bed EVER!

. Anything has to be better than the futon... We're going to try a 'medium-firm' tempur to compare firmness and then possibly order. The only way we'll know how it works is to actually try it for a while.. We can always do DSR within 7 days if we hate it but it'll cost £60-100 to return it!
I am still VERY impressed with it.Holy thread revival...
Just wondered how you felt about the ergoflex after 6 months? Too many fake reviews out there it's hard to tell what it's actually like...

http://www.rest-assured.co.uk/divans/traditional/pocket-2000-latex/
Paid £380 for a double in a Paul Simon sale earlier in the year.