Radio Replacement interface with OnStar(R) retention for select 29-bit GM(R) LAN vehicles with or without BOSE(R) sound system; In-field updateable firmware via USB (using PAC-UP); Retains OnStar(R) when the factory radio is replaced; Retains factory Bluetooth(R) (2009 model vehicles); Retains rearseat audio controls; Retains factory XM(R); Retains all warning chimes (chime module included); Retains backup sensors/park assist; Retains backup camera signal; Retains factory BOSE(R) audio systems; Retains factory premium BOSE(R) audio (Y91 digital, does not support fading); Supports nonamplified audio systems; Steering wheel control harness (prewired); Dual zone function; Chime volume adjustment (factory buttons); OnStar(R) volume adjustment; Retained accessory power output (RAP); Reverse wire output; VSS (Vehicle Speed Sense) output; Illumination output; Parking brake output; Includes antenna adapter;