For use with Screw Neck Diagnostic Bottles Advantages of an aluminum seal with the convenience of a screw cap Polypropylene screw cap with gray bromobutyl / 50 stopper Autoclavable . Cat. No. Color Cap Size . 240676-01 Black 20-400 . 240676-02 White 20-400 . 240676-03 Red . 240676-04 Blue . 20-400 . 20-400 . 240676-05 Yellow 20-400 . Qty / Case