... :of NRV series worm-gear speed reducer 1.model number:NRV030-NRV130 2.self locking 3.fast stop 4.good cooling ef NRV series ... for silver, green, and other color8)model number:NR025,NRV30,NRV40,NRV050,NRV063,NRV075,NRV090,NRV110,NRV130 NRV SERIES WORM GEAR REDUCER