These Corning® stirrers have a durable glass-ceramic 4 x 5 inch Pyroceram® top and offer superior performance and reliability in a low profile, space-saving design. Exclusive closed-loop stirring control monitors and regulates the stirring speed for aqueous, viscous, or semi-solid solutions. A stronger, larger magnet improves stir bar coupling and stirring capability. They operate on 120V/60Hz and are UL and CUL approved to meet needs in North America and other locations with similar requirements. Performance and versatility are ensured with features such as: -Microprocessor controlled to automatically adjust motor strength to any solution. -Enclosed electronics design protects components, improves performance, and prolongs product life. -Two piece casting design deflects spills away from electronics and includes a built in mount for an optional support rod (No. 400084). -1 x 3/8 inch stir bar (No. 401435) included with each stirrer. -Two-year warranty.