For Undere new mattress - this time without any means cranny - we wanted to have a solid ceiling. The duvet is very well made, variable retractable by the same leg measurements and not too thick. In warm summer nights, it is a little too warm, as it does also a single sheet, but just right on cool nights and in the coming autumn. The soft shell material adapts super the sleeper and is not as a board about this. We are very satisfied.