Air intake filters come in various shapes and sizes, depending on the engine’s requirements. They are made of various materials, including paper, foam, and cotton, and each has its unique benefits and drawbacks. Paper filters are the most common and affordable type of filter, but they require more frequent replacements than other types. Foam filters are reusable and can be washed and re-oiled, but they may not filter as efficiently as paper filters. Cotton filters offer superior filtration and are washable and reusable, but they are also the most expensive.