Rugged OHAUS Mini Hotplates and Stirrers can heat and stir up to 1000 ml of water on the 4 x 4 in. (102 x 102 mm) ceramic top plate surface. These units are ideal for educational and other lab environments that require simple, every-day heating and stirring. All models feature a built-in support rod holder with a locking knob, which accepts the optional support rod kit. Stirring models include 1.5 in. (38 mm) PTFE coated stir bar.