NVX 7-Band Graphic Stereo Equalizer 1/2 DIN with Dual Aux Input and Sub Control [XEQ7] 7-BAND GRAPHIC EQUALIZER WITH DUAL AUXILLARY INPUTS. This will allow you to play audio from an iPod, MP3 player, or other devices GOLD-PLATED CONTACTS. These contacts optimizes signal transfer that lessens interference to give you the best signal output VOLUME CONTROLS. This has a seperate master and subwoofer volume controls that lets you adjust the sound to your preferred level ISO MOUNTING HOLES. This mounting hole and removable trim ring for easy customer installation 7V PREAMP OUTPUTS. The higher the preamp output voltage rating, the crisper the signal to your speakers and subwoofers