For most mig welding you want 20cf/hr. Your left gauge is liters/min on the outside black scale. Can't see what the is under the bottom of the needle to determine what scale the red is. Based on math and what the old interweb says for conversion from l/min to cf/hr, it should be cf/hr. 20cf/hr is 9.4l/min. Adds up with the scale. Keep in mind that gauge is calibrated for argon/CO2 blend gas. If you are running pure CO2, the flow rates are a little different. Start at 10 on the black and adjust from there.