Got something similar that I used to use for sanding the cusped edge off of etch brass, amongst other things. Mine is a piece of melamine that was packing in some long lost flat pack furniture. It is about two foot long by four inches wide. Not full sheet width, but using both sides It has 800, 400, 250, and 100 grit on it. Amazing how long the WnD lasts. I think I’ve only replaced it once I. About twenty years….