Generally speaking, the interface components such as keys and display are kept inside the closed clamshell, protecting them from damage and unintentional use while also making the device shorter or narrower so it is easier to carry around. In many cases, opening the clamshell offers more surface area than when the device is closed, allowing interface components to be larger and easier to use than on devices which do not flip open. A disadvantage of the clamshell design is the connecting hinge, which is prone to fatigue or failure.