First we have to know the quality and performance of the air compressor. The quality of the air compressor can be divided into three aspects: production technology, manufacturing level, accessory selection and more. One air compressor should be cheap and profitable, can only be reduced at cost, which may have no establishment of the standardized quality system. Choosing some cheap air compressor parts will take it out and sell it. After starting, there will be problems, such as the noise vibration; oil leakage; intake valve fuel injection; host card death; high temperature; jumper; oil emissivity; oil emulsion; non-air, etc. And the cheap air compressor is definitely no reliable after-sales service, only the headache is crying without a door.