With Glass Windows On Both Opposite Sides For Observation. Temperature Controlled By Mercury Contact Thermometer With A Sensitivity Of +/- 1 Deg c. Suitable For Precision Laboratory Activities Requiring Constant Temperature With High Degree Of Accuracy. Complete Stirrer, Workable On 220 V Ac 50 Hz Single Phase. Optional: I) Digital Temperature Indicator-Cum-Controller Instead Of Contact Thermometer. Ii) Microprocessor P i d Digital Temp. Indicator-Cum-Controller Instead Of Contact Thermometer.