The 45 mm polypropylene screw cap with sealing ring are replacements for caps that are provided with Lab 45 media bottles. For high temperature applications use the PBT (polybutylene terephthalate) screw caps and the ETFE (ethylene tetrafluoroethylene) pour lips which can withstand temperatures up to 180°C. For lyophilization applications use the solid or open top polypropylene screw cap without the sealing ring and use the black lyophilization stopper.