[Architecture Building Kit] designed planet building set with sun earth moon for 6+ year old boys or girls and astronomy enthusiasts. This building kit is a science educational toy kit to inspire or improve their space astronomy, as well as a perfect planets decoration for home. [3-D Solar System] Earth, Moon and Sun orrery model could be rotated by rotating bar, earth orbiting around the sun, and moon orbiting around the earth, showing planetary orbit. Note: dont push the gears onto the axles too tightly. [Safe Block Quality] There are 461 pieces building blocks made up of ABS high quality, without smell, CPC (Childrens Product Certificate) Approved, smooth blocks' surface. Building blocks compatible with LEGO, or other major building brands. [Clear Building Instruction] Instructions are very clear and easy to follow, guiding brick by brick, you could put bricks together easily. When assembling the various gears, its important to make sure everything rotates freely, no push much too tightly.