Available in four colors, Incipio's offGRID ($70) enters the crowded field of iPhone 4 battery cases with some distinct advantages over rivals. Incipio has sculpted a glossy shell that has the look and feel of an iPhone 3G/3GS, adding only the smallest bottom lip with a Dock Connector inside, four blue lights, and a flush power button that's easy to press correctly and hard to press accidentally. offGRID is bundled with a micro-USB charging cable,…
