The ConeBoss sign can be used with 36” high cones but it may fit a little loosely as some 36” cones tend to be slimmer towards the top. Our ConeBoss signs measure 15.75" W x 8.5" H and the entire assembly is 15.875” W x 15.4375” H. The sign holder has a bottom diameter of 3.25", which snuggly fits over standard 18" and 28" high cones, the most common sizes of traffic cones.