Made of polypropylene, these 2 mL microcentrifuge tubes offer a special design to produce a more secure closure. This will help to prevent tubes from opening during centrifugation, boiling, storing, freezing and shipping. They are graduated at 0.5, 1.0, and 1.5 mL. They are autoclavable to 121 C. Pierceable lid. Etched surface on side of tube for sample identification. Large etched graduations make volumes easy to read. Improved polypropylene transparency for easy viewing of samples. Tubes can withstand centrifugation up to 15,000g.