6781 Series Gauge 5 SCREW SAE FLANGE MOUNTED GAUGE WITH ADJUSTABLE FLOAT FOR LOW PRESSURE TANKS Application The 6781 Series Senior gauges are designed for use in low pressure tanks 0-10 psig containing diesel fuel, gasoline, fuel oil and lubricating oils. Used in many applications such as construction equipment, stationary generators, boats, farm equipment and home heating. General Information & Features The 6781 Series Adjustable Senior gauges are gear-action models for top mounting. The standard float is nitrile rubber. The gauge is mounted to a mating Senior flange 2 1⁄4″ 5 screw circle. The gasket is Buna-N.