The air compressor (in English: air compressor) is the main body of the pneumatic source device. It is a device that converts the mechanical energy of the prime mover (usually an electric motor) into gas pressure energy, and is the gas pressure generating device for compressed air. Commonly used air compressors today include piston air compressors, screw air compressors (which are further divided into twin-screw air compressors and single-screw air compressors), centrifugal compressors, as well as vane air compressors and scroll air compressors. Here, we introduce five websites selling air compressors that are worth paying attention to.