Light Stax Illuminated Blocks use LED technology and are 100% compatible with classic existing building blocks of similar size. These awesome construction blocks are designed to magically light up when stacked together on the power base. Enhance Lego or Duplo creations with these brilliant glowing blocks or make new colorful creative designs! Perfect gift for the aspiring architect in your life this holiday season! After kids construct their new masterpiece it can be used as a night light with 3 different light settings including a 15 minute auto shut off. Imagination and open-ended play make this 102 piece kit ideal for kids ages 3 and up. Blocks measure 1 1/2 inches squared and come in blue, red, green, yellow, orange, and white. Comes with two power base that require 3 AAA batteries (included) and can also charge with a USB cable.