The Palm Trēo is a line of smartphones originally eveloped by Handspring, which was bought by Palm, Inc. They are now manufactured and maintained by Palm, Inc. Trēos have 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. Recent models include a built-in camera. Traditionally, Trēos run Palm OS which allows synchronization with both Mac OS X and Microsoft Windows, but newer models also have editions that run Windows Mobile.