The Martin 16 x 21 in. PEB Board Drawing Kit is the premier item in its class. It's the only parallel straightedge board that uses an anti-warp aluminum body straightedge for strength and stability. Notice the deep ribbed strips so that the unit can be adjusted over the table edge to bring the artwork into the users lap. Each side of the unit has large knobs for adjusting the straight-edge to align with the artwork/drawing and stay parallel. This board has a woodgrain top with black straightedge.