Scilogex 82120004 MX-S Vortex Mixer with Orbital 4mm Shaking Movement, 110V/60Hz, 0-2,500rpm Vortex mixer (shaker) with variable speed of 0 to 2,500rpm for gentle shaking to rapid vortexing of samples Can be operated by touch or in continuous mode Comes with a cup head for mixing a single test tube or other small vessel up to 30mm in diameter Electronic speed control maintains constant speed even during changes in load Steel base and four silicone feet provide stability and dampen vibration