These sterile 50ml Centrifuge tubes are ideal for every day lab work. Sure seal caps offer confirmation that the cap is closed and dark blue graduations are clear and easy to read. Smart, calibrated graduations are marked every 5 and 2.5ml on the tube and a large white writing area makes labeling easy. Max centrifugation (RCF) = 15,000 x g. Made from Medical Grade Virgin Polypropylene conforming to USP Class VI for chemical resistance and greater strength. Tubes will withstand autoclaving (121ºC/15psi/15min) and have a cold tolerance of -80ºC with caps on.