The Hastings HFM-201/HFC-203 series Mass flow meter (HFM-201) and controller (HFC-203) are designed to accurately measure and control mass flow over the range of 30 slm to 500 slm, without corrections or compensations for gas pressure and temperature with an accuracy of better than ±1% from the mean (±2% FS for 500 slm). Hastings mass flow instruments do not require any periodic maintenance under normal operating conditions with clean gases. No damage will occur from the use of moderate overpressures (~500 psi/3.45MPa) or overflows. Instruments are normally calibrated with the appropriate standard calibration gas (nitrogen) then a correction factor is used to adjust the output for the intended gas. Special calibrations for other gases, such as oxygen, helium and argon, are available upon special order.