Message signs are lightweight,1/8in. thick plastic Coroplast backing with vinyl graphics. The sign is held in place securely by  clips on the AF40-AF51 sign frame. AF40-AF51 Sign Base are sold separately. Interchangeable message signs change-out in seconds with no tools required, allowing you to switch your message to fit any event or situation. Easy to store away and use during school events. The perfect solution for displaying your message inside or outside the building.