... Aluminium Double Extension Worm Shaft with Flange Output Speed Reducer Worm Gearbox Reducer 2.Model:RV030,Ratio:7 ... .5-100 NMRV030 Ratio 1:7.5-1:100 Aluminium Double Extension ... and durable(6) Stable transmission, quiet operation(7) High heat-radiating efficiency, high carrying ability( ... 7.5,10,15,20,25,30,40,50,60,80,110Color:Blue/Silver WhiteMaterial:Housing-Casting iron-HT200#(Aluminium ...