Is there any noise: Hold the inner sleeve of the FZL Aluminum Cage Ball Retainer Bush，oil-free bearing with your left hand, and turn the outer sleeve with your right hand to make it rotate, and listen to the noise during the operation of the WB800 Harden Bronze Bushing. Due to the backward production conditions of most counterfeit products, the complete manual workshop operation, in the production process, the bearing body will inevitably be mixed with impurities such as dust and sand, so there will be noise or unsmooth operation when the bearing rotates. This is the key to judging whether the product comes from a brand-name product of a JF800 Oilless Bimetal Sliding Self Lubricating Bearing Bushing manufacturer that is strict in production standards and operated by machines.