Polypropylene Cryovials® offer excellent transparency and ability to withstand low temperatures. Inside threads with silicone washer ensure a secure leakproof seal so that samples are protected for long periods of time. For additional safety, cryovials are sterilized by irradiation and can be colour-coded with Capinserts. Recommended working volumes and writing area printed on each tube. Catalog Nos. 337-820-02, 337-820-04, and 337-820-10 are self-standing. Cryovials® are certified RNase-free, DNase-free, pyrogen-free and DNA-free.