From the 1941 Central Scientific Company catalogue: "Gas Meters, Wet Test, Cubic Foot, for precise measurements of gas volumes in the determination of the heating values of gases for the determination of the amounts of impurities, such as dust, tar, moisture, etc., carried by the gas. Each meter is checked against a 1/10 cubic foot bottle certified by the Natural Bureau of Standards and is guaranteed to be accurate to with ½ percent in normal operation." There were two models: the one that measured a maximum flow rate of 20 cubic feet per hour was $75, and one with two and a half times the capacity was $110.