REACT-R-SHAKER permits simultaneous, vigorous shaking of up to 44 samples in 60 ml sample bottles. The React-R-Shaker incorporates two timers. A five minute timer and a sixty minute timer. Use the five minute timer with the Extract-R-Tube. Use the sixty minute timer with the Shaker trays.The React-R-Shaker motor runs at 1725 RPM.