... have passed 3C, GS, CE , EPA , CARB , etc . Professional technology , high quality , competitive price , good service , the ... 4000PSI 5000PSI+Consumer (less than 100hrs)Semi-professional (Between 150-250hors)Professional /commercial 500hrs+Industrial 1000hrs +Occasional to frequent ... lubricate transmission mechanism , the crankshaft, connecting rod and plungers . The oil is needed to keep the pump ...