A little history lesson on the foam for foamies
wow!! that is a very expensive foam!!
Yep! Back before Flitetest got popular, Depron and fanfold foam was the staple foam for people that made scratch built foamies and businesses that made foam kits and ARFs. If you go on RCGroups, almost every old thread in their scratch built foamies section had planes primarily made with these foams. Because it was produced in the EU and was almost exclusively in the EU, people in the US went to RCFoam to buy it.
http://www.rcfoam.com/depron-and-epp-foam-suppliers/
When the Readi-Board foam craze came along, people start switching over to that foam and used that instead (ExperimentalAirlines was one of the main reasons why this stuff got so popular). During this time, fanfold eventually began getting less popular after one of the two fanfold companies, the Dow Chemical Company, discontinued it. The whole depron thing also faded out in 2015 because the Austrian company that produced it, Selit, discontinued Depron-Aero, the flat depron that was made for RC planes in favor of the giant insulation foam Depron rolls, which made the foam warped and sometimes scratched. Even though you can still get fanfold from hardware shops (it's Peter Sripol's new foam of choice), foams like DTFB and MPF dominate the kit, ARF, and scratch built foamie communities nowadays.