This is a flexible board made from thin plywood with fiberglass on the back for strength. The working surface has Velcro glued to it so you can use Hook-It sandpaper. This board works really well for fairing your cedar hull after you have taken the corners down with a spokeshave or block plane. Sandpaper included: one sheet each of 40, 60, and 80 grit. The lighter grits can be used to fair out a lump epoxy job.