These lightweight racks each securely hold 24 microcentrifuge tubes, either 0.5mL or 1.5 - 2.0mL and can be combined when multiple tube sizes are used. Each rack has locking clips that firmly connect other racks together to form larger arrays. Loaded or empty, all racks are stackable to maximize storage and to save benchtop space. Connected racks are easily transported. Racks are molded of polycarbonate for durability, are UV resistant and steam autoclavable at 121°C. Dimensions: 4.8 x 26.8 x 6.4H cm. Can be stored at temperatures down to -80°C.