The headquarters of the mobile-communications startup Helio look out over the hip Los Angeles district of Westwood. The streets are packed with teens and 20-somethings--whose business Helio covets. The company aspires to hook them on the ultimate multimedia device: something perfect for talking and messaging, gaming and Web searching, social networking and finding buddies via GPS. By the end of this quarter, Helio predicts, its year-old service, which leases space on the Sprint network, will have more than 100,000 subscribers. But the company--a joint venture between the Internet service provider EarthLink and the Korean wireless giant SK Telecom--has already burned through much of its $440 million in funding; according to a U.S. Securities and Exchange Commission filing, Helio lost $192 million last year. Now its hopes are pinned on its newest, most radical device, the fullest expression of its corporate ambitions: the Ocean.

The Ocean is hefty by today's sleek standards, pill-shaped in a market of rectangular things. The company's future will hinge on how much the intended audience appreciates those departures from conventional design. It will hinge on the layout of the device's QWERTY keyboard. It will hinge on the simplicity of the messaging and search interface (for instance, the way it allows users to start typing from idle mode). And it will hinge on--the hinges. The Ocean (which will sell for $295, plus a monthly fee of $65 to $135 for rich-media subscriptions and varying allotments of voice minutes) sports a pair of them; operated by a novel three-way spring, they enable a keyboard to slide out from one side of the device and a numerical keypad to slide out from another.