Direct replacement for factory filters, only better Mercury outboards and MerCruiser inboard engines, like other modern engines, are very sensitive to water and particulate contamination. Racor developed the Aquabloc II filter medium to remove virtually all the water and from fuel. Water contamination is separated out and drops into the bowl where a drain plug allows easy, safe removal. The element material filters dirt and debris in fuel and is water repellent to prevent damaging moisture from reaching injectors. Designed specifically for either Mercury outboard or MerCruiser inboard applications. Clear plastic see-thru bowl is for outboard installations only. Includes filter element and bowl, but not mounting head.