Sierra has the widest program in the thermal mass flow of gas. The advantage of using mass flow is that it is the mass that is measured so that it is not as necessary to compensate for pressure and temperature changes . Sierra’s program includes flow meters and flow control units for air and process gas. Over the past 20 years, Sierra has patented many new concepts and developed several unique products within thermal mass flow meters of the capillary tube type. Their thermal mass flow meters / controllers can measure and control mass flow up to 1000 slpm.