Use the Clear Overlay to highlight items or to make up your own unique Overlay designs using a permanent marker pens. Low cost, roll up, front of class, teaching resource. A dry wipe plastic overlay with holes at top, to fit onto a flip chart easel. Size L. 810mm W. 540mm. Comes with storage tube. If using over a metal whiteboard surface, then our full range of magnetic accessories can also be used (See range : Home page/accessories) If purchasing for use with the Learning with Linden whiteboard easel(code 1a)and overlay holder, then you will also need to purchase 2 battens per overlay. (Choose - Overlay Battens : Home Page/accessories).