Centrifuge tubes are used to hold various liquid mixtures or liquids containing suspended solids so that they can be spun and separated in a centrifuge. The tubes are made of polypropylene, with white graduations, a frosted marking spot, conical bottom, and screw thread cap. The capacity is 50ml and they are graduated from 5ml to 50ml. They are non-sterile. Sold in a case of 500.