Dov Moran was out jogging late one night when he got tired of carrying his BlackBerry everywhere. So Moran launched Modu Phone in Kfar Saba, Israel, and in October plans to bring out a 39-gram device that can mate with laptops, car sound systems and high-performance digital cameras. The black phone with red and green buttons may be at the cusp of a trend in personalization of mobile devices, says Dan Yachin, an analyst at IDC in Tel Aviv. Modu is readying a line of wired casings to go with the phone—a waterproof one for skiing, another with data storage and modem, another that displays heart and pulse rates along with text. Russian distributors are interested in casings for kids; Italian operators are working on designer models. Modu plans to launch the phone in Italy, Russia and Israel for €180 (including two casings). Moran is betting that consumers will like the idea of changing cell phone styles, if not the actual hardware. "People buy phones as if they were cars—signing a long-term contract and sticking to it," he says. "Modu will change this."