About 80% of the clamshell-style case is hard plastic, including a thick, clear tray with just enough room for an iPhone 5 to rest inside. It’s hinged at the bottom, with the black-bordered front piece coming down to protect the display. A latch at the top twists shut and snaps to lock the case, forming a waterproof seal. It works properly; in our testing, after about an hour of submersion, the interior of the case was bone dry. The material…