The Command PRO single-cylinder, horizontal-shaft engines are equipped with Quad-Clean—an all-inone, four-stage cyclonic, heavy-duty air cleaning system that filters air particles and keeps the engine running at maximum power. The engines also can be winter weather optimized using the filtration device, which doubles as a warm air intake system recycling heat from the muffler to keep the carburetor from freezing. Horsepower options include 7-, 9 1/2- and 14-hp versions. Kohler Engines. 800-544-2444.