Extremely powerful laboratory stirrer for highly viscous applications and intensive mixing for quantities up to 100 l (H2O). It automatically adjusts the speed through microprocessor controlled technology within the speed range of 0/6 ? 2000 rpm (two speed ranges). Safety circuits installed ensures automatic cut-off in an anti-stall or overload conditions. Continuous comparison of shaft speed to desired speed is maintained and variations are adjusted automatically. This guarantees a constant speed even with changes in viscosities of the sample.