I have been using this 12 V electric servo with limit switches built in and using a DPDT rocker switch for many years. First on the SSSC and I have one installed in the JMR Special. They are so small I welded a tab on the rear of the elevator front tube and mounted the servo in the elevator with an aluminum inspection cover on the JMR. I don't have an electrical system but do use a 12 Volt , 7 amp model airplane starting battery to power the handheld radio and GPS and the electric elevator trim servo. Used an L-16S, 12 volt, 50 mm stroke, 150 to 1 gearing, 40 lbs of force, weight 3 ounces, for the elevator trim tab. Just the right speed to set the trim with the rocker switch. Price $70 + $10 for the rocker switch. https://www.actuonix.com/category-s/1823.htm Corrected -- At first I had the specs for the P-16S instead of the L-16S that I have been using.