1. good quality 2.neccessary part of ball screw 3.large stocks Introduction : ... support Unit of Ball Screw BK,BF,EF,EK,FF,FK Fixed side: BK10,BK12,BK15,BK17,BK20,BK25,BK30 Supported ... ,FF15,FF17,FF20,FF25,FF301. Support unit of ball screw-FK, specifications the same as THK . Used on both sides ... of ball screw . 2. Heavy load of support unit-WBK, specifications same as NSK ...