The main function is to adjust the air compressor to control the pressure at which it turns on and off; users can adjust it according to their actual needs. The red part is the safety valve. The regulators on both sides of the copper fittings are for exhaust, releasing air when operated. Features - Color: Black - Size: 16.00X7.50X9.00cm / 6.29X2.95X3.54 inch - Material: Plastic, zinc alloy, copper - Rated voltage: 220V - Exhaust pipe: 6MM - Outer diameter of pressure relief port: 9.5MM - Maximum current: 20A - Working pressure: 90–125 PSI - Dual pressure gauges allow for quick pressure reading and convenient adjustment - Designed for long service life, safe and reliable operation - Features a stable design with reliable performance