Трекболы

Trackball

— a type of pointing device that uses a ball to control the cursor that can be rotated under the user's finger in any direction. Trackballs are especially useful in tight spaces where a classic mouse has no room to "manoeuvre" — for example, along with a laptop when traveling on a bus. In such situations, they outperform even another variety of “fixed manipulators” — touchpads (see the relevant paragraph): trackballs are more compact, and when working with a ball, only the finger moves, the hand remains motionless. In addition, many trackballs are ergonomically shaped and comfortable even during prolonged use. On the other hand, gesture control is not available in such devices.

Note that this category also includes combined devices — mice with a "trackball" ball (usually on its side, under the thumb). Such a manipulator can be used both in mouse format and in trackball format.