Multiposition analog stirring hot plates and stirrers from Torrey Pines Scientific feature five or nine stirring positions. The large 12” square ceramic heater tops have a temperature range to 450 °C. Five-position stirring units (Models ST15 Stirrer and HS15 Stirring Hot Plate) can stir 5–800 mL beakers. Nine-position units (ST19 Stirrer and HS19 Stirring Hot Plate) can stir 9–500 mL beakers of aqueous solutions from 100 to 1500 rpm. Each stirring position is individually controlled so different vessels can be stirred at different speeds at the same time on one plate surface. The units are available in 115 V AC/60 Hz, 220 V AC/60 Hz, and 230 V AC/50 Hz.