Quality Backstop Bearing from China. Any Interest , pls contact Ellen Zhang , ellen@chinasuma.com Tel No.: 86 18068536660 Skype: suma.com5 Changzhou Suma Precision Machinery Co., Ltd is quality manufacturer for Backstop clutch over 20 years , all items 100% inspection before shipment , and we provide 1 year warranty . Trial order is available to test quality first . If you have any interest, pls call me at any time 86 18068536660 !