Hobbyking has discontinued to the 5mm model foam board
(After I had finally mastered how to use it)
only stocking 3mm and 10mm in the smaller sheet size
That sucks, I miss having the good Depron. I just built my first plane with Fli-Power Value XPS Model Plane Foam and it wasn't bad to work with just not a super smooth finish to it, I believe it is very similar to Model Plane Foam.