The "slider" also comes in handy when you have a continuum of values that you'd like the user to choose from. For instance, if your program allowed the user to specify a background color, you might provide three sliders - one to select the level of each color (red, green, blue) to display. The slider's range of values might be from 0 to 255. You might have another slider for the user to specify the brightness, or the contrast. A slider might work well to simulate features that in the real world (the one aside from computers) would otherwise be an analog input device (such as the volume knob on a stereo).