I got a piece of flexifoam. Does Bernd have experience with it?
It says CAO #180 which means it's ceramic coated aluminium oxide and 180 grit on their scale which compares with 400-600 grit sandpaper. According to them. And if I understand it correctly. It does have similar touch to the 500 paper I have.
I'm planning to use it for knife sharpening, tested briefly with a semi-dull pocket knife. Now it's semi-sharp.:^)