AT high precision airtight tester is a non-destructive testing instrument that supports both low and high pressure testing The principle of differential pressure is adopted to detect the leakage of the product with air as the medium. The working principle is to inflate the standard and the test product to the specified air pressure, and then close the valve, after a period of stability, measure the pressure difference between the standard and the test product during the detection period, and then calculate the leakage through conversion method.