Nalgene 3123-0250 Spherical-Bottom Polycarbonate 250mL Centrifuge Bottles with Caps are ideal for large-volume cell harvesting, pelleting and protein purification. Best for low to moderate speed centrifugation of biological and chemical samples. Molded of transparent polycarbonate, these translucent bottles are autoclavable and have excellent mechanical strength properties. The spherical-bottom design facilitates pellet formation and retrieval. For use in standard rotors, the use of the Nalgene spherical-bottom adaptor (DS3124-0010) is recommended.