These heavy-duty 40mL Pyrex® conical centrifuge tubes are made with increased wall thickness for greater mechanical strength. To conform to outside diameter and overall length limitations imposed by centrifuge rotors and supports, it has been necessary to reduce the capacity of these heavy-duty tubes. Tubes are graduated to 10mL in 0.5mL divisions, and from 10 to 40mL in 1mL divisions. Graduations are in durable white enamel. Tubes have pourout spout for easy decanting.