Made from high-quality virgin polypropylene, these microcentrifuge tubes are RNase, DNase and Pyrogen free for safer use in molecular biology and other biochemical applications. Include a connected snap cap, large molded-in graduations, and a frosted surface for easier writing. Autoclavable tubes can be used in very low temperatures and with various organic solvents. Maximum RCF 20000. Amber colored tubes are suitable for light sensitive applications because they do not allow any light to pass through the samples.