T-Mobile USA Inc. is a provider of wireless voice, messaging and data services throughout the United States. It offers a variety of accessories, such as phone batteries, Bluetooth and cases, chargers, data, headsets and memory cards, among others. The company serves more than 250 million customers in the United States. T-Mobile USA Inc. is the U.S. operating entity of T-Mobile International AG, a global wireless carriers and the mobile communications subsidiary of Deutsche Telekom AG. Deutsche Telekom is one of the largest telecommunications companies in the world, with a presence in approximately 50 countries.