Sleeping/bed mat
This item is in Great Rissington GB
All the details
It seems to be inflatable, as well as having foam. I can't think why else there's a screw-down cap over a nozzle, but I also can't see how it will stay inflated until you get the cap on unless there's a valve, and if there is I can't see any way of letting it down again! As you can (just about) see it is made by Silentnight and is a single size.