... running, stepless speed regulation. Packing:1 Inner packing: high quality cystosepiment. 2 Exterior packing:thicker cardboard.3 Whole packing ... for oil, chemical, metallurgical, textile, food, medicine and health, environmental, biochemical laboratory, analysis room, education and scientific ... and Maintenance: 1 Placed correctly for the liquid bottle ( or other vessels )2 Adjustment and calibration ...