Economical unframed lap boards feature a blue XY axis dry erase grid on one side and plain dry erase on the other. These boards are durable and are an invaluable teaching aide. Write wipe and use again and again with no waste. Durable hardboard backing is warp and chip resistant. Non-ghosting dry erase surface with rounded corners and smooth edges for safety and comfort. Dry erase board measures 9 x 12 x 0.125 . Bold lines separate the board into quadrants each 14 squares x 10 squares total grid is 28 squares x 20 squares. Individual squares measure 3/8 x 3/8 . Pack of 24.