The phrase "scroll wheel" refers to a small wheel on a computer mouse that allows you to move up and down on a webpage or document without physically moving the mouse. It makes scrolling much easier and quicker. Full definition
Everything can be controlled by buttons and scroll wheels on the steering wheel, or the traditional dial and shortcut buttons housed on the center console between the seats. (cnet.com)
The first step in selling your book, especially if you're relatively unknown, is to make someone take their finger off their mouse scroll wheel when they see your cover. (knockinbooks.com)
Everything is easy to use, with the brand's familiar scroll wheel controlling all the infotainment functions. (autoexpress.co.uk)