Common thicknesses are 3mm (1/8") for colors and 3mm (1/8"), 6mm (1/4"), 12mm (1/2") and 19mm (3/4") for white. If ever the backing plates are worn, cracked or pulling due to the mast, consult your rigger. http://socialrus.com/story5758570/business-sign-materials-which-should-you-choose