This model has black wheels. The No. 4 Hi-Way Patrol was introduced in 1932 as a replacement for the No. 3 Hi-Way Patrol, a pull grader brought into the product line when Caterpillar purchased Russell Grader Manufacturing Co. in 1928. At this time, motorized graders were still in their infancy, and graders pulled by tractors were much more common. The No. 4 was the smallest pull grader in the Caterpillar product line, and was produced until 1941. It was designed for reshaping and maintaining roads, cleaning ditches, and light road building. While larger graders were commonly used by states and counties for road construction, the No. 4 found typical use by townships, farms, ranches and private businesses. The 1650 lb. weight and 8? wide blade of the No. 4 made it well suited for Caterpillar Ten, Fifteen, Twenty, Twenty-Two, Twenty-Five, R2 and D2 tractors, as well as tractors of other makes between 10 and 25 drawbar horsepower.