These domes make great additions to small robots. They are large enough to mount sensors, small circuit boards, LEDs, lamps, etc. underneath. Each dome is 2.83" in diameter plus a 0.5" mounting lip. The highest part of the dome (at the center) is about 1" tall. These were made for large projection TVs and came in to us in sealed master cartons so they are in perfect condition. Green See-Thru.