Sterile Centrifuge Tube provided by STE-Mart is made of pure polypropylene material that meets USP Class VI standards and is produced in a GMP 100,000 clean workshop. The inner wall is smooth to ensure low sample residue. The double-threaded design of the tube lid has strong sealing performance and can be operated with one hand. https://www.ste-mart.com/flash....sale/sterile-centrif