This product of ours is equipped with special air valve bags for use, and after our existing sample test, the gas flow rate of our product can reach at least 3.1L/min. The fact that your air flow rate is not up to standard is probably due to the fact that you did not buy the valve bag for this vacuum pump when you placed your order. Before you placed your order, I asked if you needed to buy the air valve bag for this product, and you answered positively that I did not need it.