Axxess GMOS-13 OnStar Interface for Select 2006-2009 GM Cadillac STS with Factory Amplified Sytem Interface designed to allow the replacement of the OEM Radio with an aftermarket receiver in 2006-2009 Cadillac STS Retains functionality of both the OnStar equipped system and Amplified system Will retain warning chimes even after removal of factory installed radio Provides a 12V switched accessory output Equipped with mute, parking brake, speed sense, and reverse output for aftermarket Navigation Radio installation