1.Outer appearance quality:it should be bright and smooth 2.Axial flee of input shaft:<0.5mm 3.Axial flee of output shaft:<0.5mm 4.Output shaft starting moment:<0.45N.m 5.Impact force resistant experiment:it should not have cracks after the impact test 6.Noise test:The noise should be less than or equal to 50dB 7:Life test:5000time conformity