Hub City's Ratio Multipliers are available in power ratings up to 20 HP and ratios from 2:1 through 7.5:1. Efficiency is 97%. Helical gearing for high torque capacity and quiet operation. Three models available with cast iron Housing, two aluminum models and one stainless steel model. Permanently lubricated. Can be used as stand-alone speed reducer or increaser. Or, provides additional reduction capacity when coupled to any C-face input worm or helical drive.