First, an internal Water Separator Drain (inside of the compressor) is NOT necessary. But it can have some benefits in two cases: 1) Screw without an integrated dryer: Using a water separator drain, we remove some water from the compressed air before it's delivered to the final area of use with less water content. 2) Screw with an integrated dryer: Using it before the dryer, some of the water gets removed before the dryer, this gives the opportunity to choose a smaller-sized air dryer. In order to ensure that our screw compressor operates as efficiently as possible, Jinjing has independently developed its own special rotor profile. Compared with other traditional rotor profile designs, Jinjing rotor can save up to 15% energy. Our precision machined large-size roller bearings help to make our air end have a long service life. All these, together with our state-of-the-art internal manufacturing processes and strict manufacturing tolerances, provide excellent quality synonymous with the Jinjing name. Jinjing adopts an international advanced frequency conversion module, a special motor with speed up and down characteristics, and a set of PID parameters especially suitable for screw compressors. The control software has been tested by hundreds of thousands of compressors, with simple parameter settings and a friendly man-machine interface. The cooling of the frequency converter is specially designed. In order to support the user to set the best working pressure, the filtering area of the filter element of the oil-gas separator is increased.