Single-use 3L stirred tank bioreactor consists of a hemispherical polycarbonate container, a multi-port high-density polyethylene (HDPE) top plate, a scope marine impeller, open pipes and sintered ejectors, weldable C-Flex tubes, and all necessary gas inlet and outlet filters. Since the container is a molded part, additional ports have been added below the minimum working volume level, including a Luer-actuated sample port, a liquid inlet / outlet port, two liquid addition lines, direct jet lineS, and a harvest line . All gas and liquid addition ports below the minimum working volume are fitted with check valves to ensure unidirectional flow of gas or liquid. The CellReady 3L bioreactor is pre-assembled, gamma-irradiated and shipped, ready to use.