Panline Alex Prism Bases measuring 9 x 9 in. stimulates kids imagination with multicolored luminous base plates. Base plates come in blue, green, red and yellow colors are designed to radiate when light passes through them. Bases are used to allow maximum amount of light through to radiate the distinctive colors of prism bricks. Product is designed for children in age group of 2 yrs and above, 4 per set.