The qualified cylinder liner should have good appearance and no damage to the chrome coating on the surface. NS Company received this batch of cylinder liners, and through testing, it was found that there were scratches on the chromium plating layer on the surface of the product, which affected the use, and the product failed to meet the requirements stipulated in the contract. After negotiation between both parties, it is allowed to return all the 363 cases of defective cylinder liners to Hangzhou Biguo Parts Co., Ltd.