range classes of laptop computers, mobile smartphone like HTC or the Apple iPhone, and the availability of standard touchscreen device drivers into the Symbian, Palm OS, Mac OS X, and Microsoft Windows operating systems. Pressure-tracking pointing devices Isometric Joystick In contrast to a 3D Joystick, the stick itself doesn't move or just moves very little and is mounted in the device chassis. To move the pointer, the user has to apply force to the stick. Typical representatives can be found on notebook's keyboards between the "G" and "H" keys. By performing pressure on the TrackPoint, the cursor moves on the display. Other devices A light pen is a device similar to a touch screen, but uses a special light-sensitive pen instead of the finger, which allows for more accurate screen input. As the tip of the light pen makes contact with the screen, it sends a signal back to the computer containing the coordinates of the pixels at that point. It can be used to draw on the computer screen or make menu selections, and does not require a special touch screen because it can work with any CRT display. Light gun Palm mouse – held in the palm and operated with only two buttons; the movements across the screen correspond to a feather touch, and pressure increases the speed of movement Footmouse – sometimes called a mole – a mouse variant for those who do not wish to or cannot use the hands or the head; instead, it provides footclicks Puck, similar to a mouse, but, but designed for absolute positioning rather than relative. It typically has a transparent plastic with crosshairs for precise positioning and tracing. Pucks are most commonly used for tracing in CAD/CAM/CAE work. Eye tracking devices – a mouse controlled by the user's retinal movements, allowing cursor-manipulation without touch Finger-mouse – An extremely small mouse controlled by two fingers only; the user can hold it in any position Gyroscopic mouse – a gyroscope senses the movement of the mouse as it moves through the air. Users can operate a gyroscopic mouse when they have no room for a regular mouse or must give commands while standing up. This input device needs no cleaning and can have many extra buttons, in fact, some laptops doubling as TVs come with gyroscopic mice that resemble, and double as, remotes with LCD screens built in. Steering wheel – can