The Donaldson P551437 is a high-performance fuel filter and water separator designed to protect engines by efficiently removing contaminants and water from the fuel supply. This genuine Donaldson filter ensures optimal fuel system cleanliness and engine longevity. It features an outer diameter of 78 mm, a length of 135 mm, and a 13/16-16 UN thread size. This filter is a direct equivalent to John Deere part number RE509208 and is suitable for a wide range of John Deere agricultural and construction equipment.