The Palm Treo // (stylized as Trēo) is a discontinued line of smartphones originally developed by Handspring, which was bought by Palm, Inc. They were then manufactured and maintained by Palm, Inc. Treos had a number of integrated features such as the ability to check the calendar while talking on the phone, dial directly from a list of contacts, and send email messages. The final models included a built-in camera. Treos ran Palm OS, but later models also ran Windows Mobile. The Palm Pre, released in June 2009, replaced the Treo series.