OptiMA 12" x 18" Double Sided Dry Erase Student Lap Board with XY Grid Made in the U.S.A. 4 Quadrants Broken into 77 Blocks. 7 Blocks High x 11 Blocks Wide - 308 Blocks Total X Y Axis lines are bold black lines approximately 1/8" thick Grid lines are approximately 3/4" x 3/4" printed in a lighter gray Double Sided - Print on side A / Plain White on Reverse Side