SDP/SI - Stock Drive Products/Sterling Instrument is a U.S.-based manufacturer of power transmission and motion control products, serving customers since 1950. The company specializes in precision gears, high-quality mechanical components, gearboxes, and the assembly of both mechanical and electromechanical subassemblies. SDP/SI is part of the Designatronics family of brands, offering a wide range of stock mechanical component options and customized solutions to meet diverse engineering needs.

WD bearing is a technology-oriented group company, specialized in R&D, manufacturing, sales and service of high quality bearings. In order to make WD as a symbol of quality, WD keeps investing in advanced CNC equipment and comprehensive precision inspection devices. We commit ourselves to building a high quality employee team and bringing in advanced technique of manufacturing and management from USA, Europe and Japan.