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 ß 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.