A postage meter is a mechanical device used to create and apply physical evidence of postage (or franking) to mailed matter. Postage meters are regulated by a country's postal authority; for example, in the United States, the United States Postal Service specifies the rules for the creation, support, and use of postage meters. A postage meter imprints an amount of postage, functioning as a postage stamp, a cancellation and a dated postmark all in one. The meter stamp serves as proof of payment and eliminates the need for adhesive stamps.