First used by postal services to expedite and automate mail processing, mail sorting systems are now also used by corporations and other mailers to presort mail prior to delivery in order to earn discounts on postage. In the United States, for example, presort discounts can reduce the cost of First-Class Mail from $0.42 to as low as $0.324. Many companies also use mail sorters to handle incoming mail such as checks, orders and correspondence.