Tube racks have openings of various sizes to accommodate a specific tube diameter or a range of tube diameters. They securely hold tubes on benchtops, or in water baths, incubators, or refrigerators. Test tube racks are available in various configurations, shapes, and sizes. Options include stackable, angled, grips for inversion, and alphanumeric labels. Test tube racks can be made from variety of materials, including plain or epoxy-coated metal, wood, foam, and various acrylics and plastics. Hold a full load of test tubes or centrifuge tubes with Thermo Scientific™ Nalgene™ Unwire™ Polypropylene Test Tube Racks. Handle and transport 200 mL centrifuge tubes in the fitted Thermo Scientific™ Nunc™ Conical Tube Rack. Protect your test tubes and their contents with flexible-cavity Thermo Scientific™ Sterilin™ Test Tube Holders.