Thermo Scientific™ Nunc 15 mL and 50 mL Conical Sterile Polypropylene Centrifuge Tubes are state-of-the-art, high-quality conical tubes that are environmentally friendly, clean, come with recyclable plastic racks, and feature the largest writing area on the market for improved traceability . Nunc labware is made from high purity resin and injection molded using our advanced process. Plastic labware is a safer alternative to glass without compromising accuracy.