Encourage hands-on experimentation and observation while introducing Science/STEM activities at home or in the classroom. Sturdy test tubes feature a flat bottom for stability. Set includes a convenient storage rack so children can easily carry their experiments from place to place and a reusable cleaning brush to make clean-up a breeze. Flat bottoms allow test tubes to stand on their own. Coloured stoppers click into place for no-spill experiments. Easy to clean and store. Activity Guide includes 4 kid-friendly experiments. Set includes: 6 Flat-Bottomed Test Tubes, 6 Different-Coloured Stoppers, 1 Reusable Cleaning Brush, 1 Test Tube Rack, and 1 Activity Guide. 15 pieces total. Ages 3 and up.