Carburetor diaphragm for some of the horizontal shaft 3.5 horsepower to 5 horsepower engines. This diaphragm replaces part # 270026, 272538, 272637, 4157, 4168. This diaphragm fits 3.5 horsepower models 90200 to 90299 and 91200 to 91299. Also fits 5 horsepower models 133200 to 133299 and 135200 to 135299. If your model number is in between these numbers listed then it is the correct part for you.