1.Worm gear box adapts to i.S.O standard so that ia can change parts easily.. 2.Housing of worm gear box made by casting, moreover.It bears up against thrust due to superior quality and sophisticated design. 3.Regarding gear, it makes the gear box relax from noise under optimum heat treatment & precise grinding. 4.Stem nut(bush) is not uni-body but separated so that isolable type enable bush to be convenient, efficient and so on. 5.Protection grade can be ip65. 6.Hand wheel is optional index.