Message signs are lightweight,1/8" thick plastic Coroplast backing with vinyl graphics. The sign is held in place securely by Integral clips on the FS300 sign frame. FS300 Sign Post & 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.