There's also a small wheel on the device that is used to scroll through messages or to move between menu items. Pressing the wheel is the equivalent to clicking a mouse button. The device can also beep or vibrate to indicate incoming messages. The bit-addressable display shows six or eight lines of up to 30 characters each. The display often shows icons or larger type, but you can set it to show more lines and smaller type, depending on the mode you're operating in.
Menus are big, for example, while e-mail messages are in small type.
In a well-lit environment, the BlackBerry's screen can be tricky to read. Its very dim backlighting is only suitable for use in virtually complete darkness. The device is powered by a single AA battery. The company claims 500 hours of life on a battery. We operated it for more than three weeks on a single cell, being careful to turn it off in the evenings.