25mm x 150mm borosilicate glass culture tube with clear slide-on cap. These autoclavable culture tubes are the highest quality tubes on the market and the industry standard for long-term culture storage. Their large size allows for longer viable storage of culture slants than smaller tubes. They are extremely easy to work with which makes transfers a breeze. Once the cap is installed on the culture tube, it should be wrapped with Parafilm to protect against contamination while still allowing for gas exchange. This product can be sterilized and reused over and over again. We also sell culture tube racks that are specifically designed for these tubes. Perfect for the long-term storage of cultures via a culture slant.