The Culture Vessel System consist of three (3) NALGENE¨ Products and includes a 12L Culture Vessel with Ports; 1/8 HP Overhead Drive BioTech Mixer and a Lower Assembly with 13-1/2-in. shaft (3/8=in. diameter) with 4-in. axial flow glass-filled polypropylene impeller and a 2-1/2" wide polypropylene baffle for excellent top-to-bottom mixing. The BioTech Mixer provides variable speed, programmable speed/duration control, clockwise and counter-clockwise rotation and is specifically designed for maximum efficiency with system components.