For a firm, positive closure with a universal cap, turn to our versatile cap closures. Whether you want to seal inside the tube or over the tube rim, these one-size caps fit a wide range of tube sizes, making them ideal for laboratory standardization. They can be sealed with just one hand under various temperature and storage conditions. They provide a strong seal to help ensure sample integrity while preventing loss due to evaporation. Same cap fits 10-mm, 12-mm, 13-mm and 16-mm tubes. For use with glass, plastic, and blood test tubes.