Scroll wheel vs. Explicit Scroll Buttons (OR BOTH!)

1. Which device has two buttons and a scroll wheel?
2. What is the scroll wheel on a laptop?
3. What does the button under the scroll wheel do?

Which device has two buttons and a scroll wheel?

The scroll wheel that is located in the middle of the mouse is used to scroll up and down on any page without using the vertical scroll bar on the right hand side of a document or webpage. The scroll wheel can also be used as a third button on the mouse.

What is the scroll wheel on a laptop?

A scroll wheel is a wheel used for scrolling. The term usually refers to such wheels found on computer mice (where they can also be called a mouse wheel). It is often made of hard plastic with a rubbery surface, centred around an internal rotary encoder.

What does the button under the scroll wheel do?

It unlocks the scroll wheel, so that it can spin freely. Useful for scrolling on longer pages, long PDFs, etc.