The quick fill uses two 3" holes in the stern that connect to a valve designed for RV septic use. The Drainmaster is designed to dump the gray and black water out of the RV's holding tanks. It was incorporated into the marine industry as an electric gate to flood and empty the quickfill ballast tanks but the gears in the vales are week and fail either holding watering the tanks, not opening or either remaining open. Complete Junk! The Valterras seem to have a better and more hardy gears and is the replacement for the drainmasters. Then you move into the auxiliary valve that can be used manually, the drainmaster used manually needs a small Allen key to open and close the valve which was also junk so an additional valves added to the set up for when they fail. Valterras design uses a pull pin and slight rotation of the handle for auxiliary manual use.