Eppendorf® Biopur Safe-Lock™ Centrifuge Tubes provide the highest biological purity category. This is achieved by a fully automated production process under clean room conditions and the subsequent environmentally friendly √ü sterilization. The patented hinged lid on these tubes eliminates any danger of leaks. Safe-Lock Tubes ensure absolute safety when working with expensive or toxic samples, radioactive substances, or DNA. The 0.5 mL, 1.5 mL, and 2.0 mL test tubes have¬†volume¬†graduations and etched marking surfaces. All tubes are individually sealed.