Many people thought that cars, as the dealer sold them, were inefficient or lacked much-needed accessories. Model T owners sent the Ford Motor Company ideas for improvements, and hundreds of mail-order gadgets and attachments allowed owners to upgrade the Model T or make it work better. Inventors fashioned devices that claimed to make cars safer, more fuel-efficient, or easier to use. Some of these devices later became standard features on cars. Others remained popular add-on items, and still others failed to catch on.