Second,see the specification model.When selecting accessories,it is necessary to observe whether the specification model meets the requirements for use.Some are almost the same from the outside,but they can't be used without paying too much attention.
Third,see if there are assembly marks.The qualified product assembly mark is very clear and obvious.Such as the gear assembly mark,the top mark of the piston,etc.should be clear and complete.Unmarked and unclear marks must not be used.
Four to see if there is no corrosion.Some parts may be rusted,oxidized,discolored,deformed,or aged due to poor storage or long storage time.If any of the above conditions cannot be purchased.Five to see whether there is distortion.Such as tires,belts,shafts,rods and other storage methods are not appropriate,it is prone to deformation,geometrical dimensions can not meet the requirements of the requirements,it can not be used normally.
