3.39 * 3.39 in flexible square with big round button of 2in diameter, letting simple enlarge fashion. ^^ The super big attractive button with 2in diameter, and the sensitive touching reaction, making the calling more convenient. ^^ 360 degree water-proof handling and the simple pushing bottom base without screws showing the humanized design and making it simple to change batteries. ^^ Simple and stable login mode, the phenomenon of messy code does not appear. Signal is stable and long distance.