1) High accuracy worm gear and worm shaft 2) Less noise and lower temperature increase 3) High quality aluminum alloy die cast large speed ratio :5,7.5,10,15,20,25,30,40,50,60,80,100model sizes :025,030,040,050,063,075,090,110,130,1501.high quality aluminum alloy cast housing from 025-090 die cast iron housing from 110-150 high quality Tin Bronze worm wheel2.high eiifciency and high reliability ...