Equalizer allows you to set a preferred preset, or enable it to auto-detect and match the preset to the type of music you're listening to. You can also set your own custom preset, or even use the equalizer for a little finer control over the audio pumping through your device.
Tapping on the power icon along the top will allow you to turn on or off different aspects of the app. For example, this is where you would go to enable bass booster, a virtualizer and reverb. You can then fine-tune these settings under the Effects tab.
You can also set equalizer widgets on your homescreen for fast access to the app. With the larger widget you can enable/disable the equalizer directly from the home screen without having to launch the app.
Customize your audio and get the exact sound you want from your Android device, all for free. Can't beat that.