Dry Erase board surfaces are white porcelain enamel steel. Recommended for use with liquid chalk markers, and erase with standard eraser. Graph system rulings are permanently silk-screened. Graph lines are black; X-Y axes lines are yellow. Board frames are anodized aluminum. With wall hangers, or may be set in a chalk trough. Magnets can be used. Pattern of 40 high X 46 wide squares with 1 inch sides. Shipped by Fedex.