This heavy duty, all polypropylene rack provides efficient and extended cooling of twenty-eight 15 ml or 50 ml centrifuge tubes in a chilled bath. The deep bottom tray holds approximately 2 liters of ice flakes and water so that tubes can rest on the bottom of the tray for maximum stability and exposure to the bath. A flat perimeter rim provides space for labeling tape. The rack is steam autoclavable at 121°C (250°F) and stackable with identical racks when full or empty. To further protect tubes during transport or storage while also maintaining stackability, an optional polypropylene cover is available (order separately).