Technical Structure Air Tank: The large red cylinder at the bottom is the tank where compressed air is stored. Motor and Pump Unit: The black and gray compartment on top contains the motor mechanism that compresses the air. Pressure Gauges (Manometers): Two circular gauges on the right allow you to monitor the air pressure inside the tank and the output pressure. Pressure Regulator: The red-valved mechanism used to adjust the power of the output air.