Profile of AU Parametric EQ
Apple's Parametric EQ is a parametric EQ filter effect included free with Mac OS X. The plugin includes a bell-shaped peak or notch band-pass filter with an adjustable center frequency, gain, and "Q" to control the width of the peak or notch.
The plugin is installed with Mac OS X, and it's available in most audio editing applications. Usually the plugin is drawn with a simple white background. GarageBand draws it in gray and adds a decorative image at the top (shown here).