Foredom Manual Speed Control EM-1. Foredom's table top variable speed control is constructed of heavy duty plastic. It has a dial control for precise speed settings, as well as good repeatability of previous settings. For use with 115 Volt M.SR, M.SRB, M.SRH and M.SRBH motors. The EM-1 can also used with a Dremel 731 flex shaft tool to vary speed. Dimensions 5″ long, 5-7/8″ wide, 2-3/4″ high