We bought the FabiMax Fitted Sheets 90x55cm for matching FabiMax foam mattress (90x55cm !!!) and are bitterly disappointed. The sheet is too small and can only be tightened using brute force on the mattress. The mattress bends of course significantly through because they A: is not concrete and B: no 500kg baby it is.
The vague hope that after the first wash the fabric slightly yields, has not been fulfilled. We refer now still the mattress once so, complain this and hope that maybe sets improvement to the birth of the child. So - as it is now - it does not work anyway.