ALLOWS DIRECT INTERFACE OF ANY PRE-AMP LEVEL AUDIO SOURCE TO A FACTORY RADIO WITH A SLAVE UNIT ELIMINATING THE NEED FOR SOUND-DEGRADING SOLUTIONS LIKE AN FM MODULATORINTERFACES INPUT SOURCES FROM DVD VCP MP3 SATELLITE RADIO OR PLAYSTATIONLOWER COST & HIGHER QUALITY SOUND THAN AN FM MODULATORCOMES WITH A 3-POSITION SWITCH BETWEEN 2 AUX INPUTS & THE FACTORY SLAVE UNITHIGH-QUALITY AUDIO ISOLATION IC ELIMINATES ENGINE NOISEINTERNAL CMOS ELECTRONIC SWITCHING FOR LONG-TERM RELIABILITYREQUIRES FACTORY XM RADIO RECEIVER FACTORY DVD REAR SEAT ENTERTAINMENT OR FACTORY/AFTERMARKET CD CHANGERIN ORDER TO WORK SLAVE UNIT MUST CONTINUOUSLY BE PLAYING OR XM RADIO OR DVD MUST BE ONFOR 2003 GM CLASS IIUPC : 606523105743Shipping Dimensions : 8.50in X 4.00in X 1.50inEstimated Shipping Weight : 0.3625