Mini Vortexer features * Low Vibration, Quiet Operation * Convenient One-Hand Use * 200 to 2500 rmp Range. Ideal for a wide range of intensive mixing operations. Supplied complete with cup head for use with single tubes, and platform head which accommodates beakers, flasks, and other small vessels. Simply set speed with knob. Unit starts automatically when tube is pressed down to center of adapter; motor stops when downward pressure stops. Rubber footing holds unit securely to surface and reduces vibration transfer. Motor speed is electronically stabilized and will not change due to manual pressure. 230V. UL and C-UL listed. CSA certified.