The Treo 600 is a smartphone, combining a color Palm OS PDA with a regular sized mobile phone. It was developed by Handspring, and offered under the palmOne brand (now Palm, Inc.) after the merger of the two companies. It has a number of integrated features and it is possible to check the calendar while talking on the phone, dial directly from contacts list, take pictures or send emails. It includes a five-way navigation button and favorites screen allowing quick access to the phone functions.