30"X30" are made of .080 aluminum with high intensity prismatic sheeting or diamond grade sheeting. Engineer grade signs have an average lifespan of 7 years while the high intensity prismatic signs have an average lifespan of 10 years and are 10x brighter than engineer grade. Diamond Grade signs are lime-green in color and 3x brighter than high intensity prismatic. All signs have pre-punched holes ready for quick mounting.