This 100 Square can be used with 'Magnetic Numbers,' 'Cover Squares' and marker pens. There are counting lines above and below. Most popular overlay in the range. Made from a tough semi-rigid plastic, these new overlays are long lasting and self-supporting, so that they can be propped up in front of any whiteboard or big book easel. They can also be hand-held or fastened to a wall. Compatible with the majority of whiteboard markers. Size: 720 x 635mm Please Note: These Overlays should be stored Flat Also available an Easel (code 1a) and Table Top Whiteboard (code 300), with rear storage area for the overlays.