This model will hold two culture vessels up to a maximum size of one liter. As well as continuous stirring fully controllable up to 80 rpm, the stirrers incorporate fully variable interval stirring. You can choose "on" times between 6 seconds and 5 minutes, and "off" times between 2 minutes and 2 hours. Automatic cycling improves cell yields in certain conditions, particularly during the attachment stage. In addition, it has calibrated speed control and interval stirring, all solid state controls, polished stainless steel housing, strong, rugged and lightweight - built for years of use.