Both products accomplish this through use of a small wheel that functions as a third mouse button. To move up or down in a document or application, you simply move the wheel forward or backward. You can set the amount of movement each detent produces in the readily available setup program. In the Logitech version, the wheel is also a switch. While Windows 3.x users can use some of the other features of the product, such as enhanced mouse pointers, scrolling is only available on the later Microsoft operating systems.
Installation is easy.
The product is fully configurable for right or left-handed users. There are two configuration options that are worth a special comment. This option allows either mouse button to easily perform any one of eight functions that normally require you to move the mouse to a particular part of the screen and click a special button. Some of these functions are very convenient. Fortunately, you do not have to go to a lot of trouble to get them back.