Tracker+Ball

=__Tracker-ball__=

A tracker-ball is an input device where you use your finger to rotate a ball. It moves a pointer on a screen. (It is like an up-side down mouse!) Tracker-balls are used by children and adults that are perhaps just learning to work with computers or have a mobility problem. The tracker-ball may reduce the strain on the hands, arms or shoulders of the elderly. It is especially useful for students that have uncontrolled movements. They can anchor their hands onto the body of the tracker-ball and move that ball with their fingers.

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__Advantages and Disadvantages:__
Advantages:
 * Takes up less space than the regular mouse.
 * Helps people with disabilities learn to use computers.
 * Offers comfort to the user.
 * Easy and simple to use.

Disadvantages: (an example of company is Logitech.)
 * Becoming extremely hard to find nowerdays. (only a few companies are producing the tracker-ball today.)
 * They are expensive.