Our outboard motor muffs are the perfect solution for running your engine before or after using it. Quality construction offers flexible large 3.7" diameter round ear muffs that rotate within the U channel or 3 1/4" by 5" rectangle ear muffs . The U channel fits almost all outboard or inboard/outboard I/O engines with a 9 1/4" measurement from the inside of the channel to the center water holes. The motor flusher easily connects to a standard garden hose with the included washer. Comes with an option quick connect adapter to use with quick connect hoses. This flusher offers superior water flow to other flush adapter solutions. Perfect to use for winterizing your boat or just idling before or after a run. Simulate submerged settings or fake a lake with the easy muffs. Wash away salt and dirt from your engine lines. Better Boat is an American owned company offering superior boat accessories marine grade and boat cleaning products. We completely stand behind our products and our customer service. Thanks for considering our ear muffs for outboard motors and other boat parts accessories.