CELLTREAT Flip Top centrifuge tubes are manufactured in a class 100,000 clean room and made of high-clarity polypropylene. Graduations are printed in a bold easy-to-read black and are accurate to ± 2%. Large white marking area provides excellent contrast for identification. The ergonomic leak-free flip top cap design allows easy one hand opening of caps while preventing loss of a separate cap. Flip top caps are smooth, flat surface polyethylene. Temperature range is -80°C to 120°C. CELLTREAT 15 ml and 50 ml Flip Top Centrifuge tubes are available in either paperboard recyclable racks or bulk packaged in sterile re-sealable (zip closure) bags. Gamma irradiation sterilized, RNase-free, DNasefree, and Non-pyrogenic.