... 4.good cooling ef NRV series worm-gear speed reducer,such NRV025, NRV030 gear reducer, gear speed reducer Features: 1) High quality ... gearbox 2) High accuracy worm gear and worm shaft 3) Less noise and lower temperature increase 4) Easy mounting and linking, high efficiency 5) ... Wooden caseYou also can order color for silver, green, and other color8)model number:NR025,NRV30,NRV40,NRV050,NRV063,NRV075 ...