Standard foamcore boards (made by Elmer's) for a really good price. Packaged well and delivered on a wooden pallet, the boards had minimal edge damage / denting, but since these are thinner (3/16 inches, less than half as thick as the larger, sturdier, much more expensive boards), they tend to curve or warp easily, especially when standing upright and leaning on a wall. When mounted at all four corners they remain flatter. Easy to mount with Command Hook velcro strips. Be careful using pins or thumbtacks, because most tacks are longer than the thickness of the board and will poke the whole way through, possibly damaging the wall behind the board.