Plastic test tubes for laboratory tests; Round bottom with screw top on the top. Perfect for samples, food colors, craft use etc. These are made for use as centrifuge tubes and are therefore leak proof. The non-wetting inner surface eliminates concave menisci, more accurate measurements. The change from glass cylinders to the plastic equivalent Globe severely rupture and reduce the potential for injury. Chemically resistant to most acids, bases and many common solvents. Size: 12 * 60mm (bottleneck outside diameter * test tube height) Bottleneck diameter: about 1cm / 0.39inch Test Tube Color: Transparent Cap Color: Red Material: Plastic Package Contents: 20 x plastic test tubes Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.