Tri-Fold Bed MattressThis folding mattress fits all steelpods. As you extend the bed, the mattress simply folds over to complete the bed. If you browse the forums, there are plenty of unhappy people struggling to find a comfortable sleeping arrangement. Rock'n'Roll beds and pop tops are just not the nicest things to sleep on. We wanted to make a really comfortable mattress. With 8cm thick high density foam, we think it's one of the thickest on the market.