Replaces Factory Radio While Retaining Onstar ; Plug-&-play, No Cutting Or ;splicing Into Factory Plug ; Pacos2/pacos2 Bose Communicate Directly With The Onstar Module To Prevent False ;triggering & Eliminating Unwanted Audio Noise ; On-board Amplifier Will Drive Two 4w Speakers In Stereo ; Use With The Existing Factory Speakers Or External Speakers;for 2003-2004 Cadillac Escalade, Escalade Ext, & Escalade Esv; 2003-2004 Chevrolet Avalanche, Silverado, Suburban & Tahoe; 2002-2004 Trail Blazer With Bose; 2003-2004 Gmc Envoy, Sierra, Sierra Denali, Yukon Denali & Yukon Slt; 2003 Hummer H2; 2004 Hummer H2 (will Need A Cm1 To Retain Warning Chimes)