C2603. Conical 50ml centrifuge tubes are made of premium polypropylene for clarity and centrifugal strength. They are supplied sterile. The tubes are autoclavable but the polyethylene screw caps are not. Tubes and caps may be frozen at temperatures as low as -45 degrees C. The maximum centrifugal force for both 15ml and 50ml tubes is 9000xg. Caps have a flat top for easy marking and labeling. CASE of 500 loose in a sterile bag.