Make up your own Overlays by writing onto thin card and then stick to the underside of a Clear Overlay, and attach by using double-sided tape. Alternatively you could use a permanent marker directly onto the overlay to create an image you can then write and wipe over the top what you like on the surface using a dry wipe pen. Size H.850mm W.540mm. BATTENS: Battens help to keep the overlays flat during use and must be purchased if using the overlays with any of our overlay holders. ALSO AVAILABLE: With battens. As a single item.