These disposable conical-bottom and freestanding tubes feature easy-to-read graduations and smooth inner walls for easy filling and sample preparation. Rack-packed tubes are packaged in freezable, recyclable, autoclavable racks, and stackable rack designs make them ideal for benchtop organization. Caps are available in either flat or plug styles. Certain models are designed to provide protection for light-sensitive samples, manufactured from a dark polypropylene. These high-quality, high-performing centrifuge tubes are ideal for maintaining a secure seal when using shakers and horizontal incubators.