The big magnetic stirrer MPS-1 with digital tachometer is an ideal instrument for extraction and dialysis of enzyme solutions, as well as mixing of other chemical and biological substances in big quantities. The rotation speed is controlled with an electronic feedback and monitored by digital display. The big magnetic stirrer MPS-1 with digital tachometer is applicable in all areas of laboratory research & education in biotechnology, molecular biology, biochemistry, microbiology, chemistry, medicine, gene engineering.