This version of our AC Powered Stop Sign incorporates our small LED lights surrounding the perimeter of the stop sign. The sign is constructed of heavy duty aluminum, with 3M Hi Sheeting, sealed to prevent any outside elements. Donít let the small LEDís deter you from taking a closer look at this sign. With our patented technology Solar Traffic Systems Inc. has engineered this sign to be visible up to 2 miles away. The great thing about this sign is that when it isn't flashing it still acts like a regular stop sign. Measuring 24".