BE AMAZING TOYS-Rainbow Tube Science Kit. Use coloring tablets to make colored water, grow clear and colored crystals, and make a rainbow test tube using your colored crystals. This kit contains rainbow tablets, crystal mix, one 6x1 inch test tube, and instructions. Conforms to ASTM F963. Recommended for ages 4 and up. WARNING: CHOKING HAZARD-Small Parts. Not for children under 3 years. WARNING: This set contains chemicals that may be harmful if misused. Use only with adult supervision. Imported.