Reference: T311-2 White washer seal fits tightly on top of the tube opening to ensure a leakproof seal Made of medical grade, non-cytotoxic, USP class VI and FDA compliant polypropylene BSE/TSE BPA, phthalate, Latex and Heavy metal free Sterilized by Gamma radiation and Autoclavable Certified RNAse, DNAse, DNA and Pyrogen free