1.high quality 2.low friction 3.low noise 4 ... parts, in the use of the necessary screw support unit, nut bearing, lock nut and so on also ... , are based on strict quality assurance system to manage, therefore it has a high reliability.about Shengyue: CompanyShanghai ... improve our quality and after-sale service,we have confidence in cooperating with every potential customer. High quality ,Ball Screws ...