This is a replacement air filter/AC cartridge for your small engine. The air filter prevents dirt and debris from entering the engine. Over time, the air filter can become clogged or damaged, and this can lead to reduced performance. This air filter is approximately 4 inches wide and approximately 5 inches long. To replace the air filter, locate the air filter cover on the side of the engine, unscrew it, and remove the old filter. Be sure to clear out any dirt, clippings, or other debris that has found its way into the air filter assembly before you insert the new filter. Reattach the air filter cover, and secure it with the screws. This product is sold individually.