With a Grid of 12 squares vertically and 20 horizontally this Blind could be used as a hundred square, multiplication square, and much more. HOW THEY WORK: These giant sized overlays work in the same way as a conventional roller blind. They can be pulled down in seconds to cover a wall mounted whiteboard or blackboard or even a smooth wall surface. The blind material clings to the hard surface behind, creating a hard writing surface. Made from a special gloss plastic that will accommodate the majority of dry wipe marker pens. FITTING AND CHANGING THE BLINDS: Two mounting brackets (supplied) are fitted to the wall above the board or wall area to be covered. The rolled up blind can be clipped into the brackets immediatley ready to use. Swapping one blind for another is very straightforward too and can be done in seconds. Supplied in a colourful plastic storage tube, in which the Blinds can be stored while not in use. Blind size: Width 1750mm, Height 1250 Printed Area: Height 900mm, Width 1500mm approx.