Reversible polycarbonate cooler racks feature one side designed to hold 1.5- or 2-mL tubes while the other side holds 0.5 mL tubes. The 4 x 5 grid keeps up to 20 tubes upright and secure. Racks are filled with an inert, non-toxic gel to help maintain a consistent temperature. Translucent lid cover allows you to easily view and identify samples without removal.