TSI 4146 Primary Flow Calibrator to ensure the utmost accuracy and compliance of your air sampling pumps. This primary standard device provides continuous, real-time volumetric flow readings, allowing for fast and effortless calibration directly in the field. Covering a wide range from 0.01 to 20  liters per minute (lpm), it is the essential, field-portable tool for guaranteeing the integrity of all your industrial hygiene air samples.