Polypropylene Cryovials® offer excellent transparency and ability to withstand low temperatures. External threads with silicone gasket ensure a secure leakproof seal so that samples are protected for long periods of time. Cap features a long skirt for one hand aseptic technique, and an inside thread design that will not contribute to possible contamination. A specially-designed lip in the interior of the cap ensures a leakproof seal for these cryovials even at very low temperatures. There is no silicone seal. Tubes are provided with a white marking area for sample identification and can be colour-coded by the use of Capinserts. Cryovials® are certified RNase-free, DNase-free, pyrogen-free and DNA-free.