When do some experiments and this avoids the whole broken glass issue. The plastic test tubes with a tight fitting cap, no rough edges, they are water and air tight, have a good seal. Great for making scientist concoctions. Also can be used as birthday goody bag gifts. Features - Material: PP. - The product is made of PP material, safe, durable and sturdy. - The test tubes are with accurate scale on its body, which is easy for you to read the accurate liquid volume. - You do not need to worry about liquid leaking because each screw is leakproof. - It not only can be used for school, scientific laboratory using, but also for holding small items. - Great choice for decorating Halloween Christmas festival, scientific themed kids birthday party supplies and decorate the house. Package list: 36 1 x 36 holes box bracket