If 2 goes into the factory and is added to 3, what comes out at the other end? 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.