PAC C2A-GM24 GM Class II Add An Amplifier Interface 2003-05 GM Digital Amplifier Interface Provides Line Output for Adding a 2-Channel Amp Full Range Audio Signal, Not Bose Specific Compatible with: 2003 - 2005 Denali, 2003 - 2005 Escalade, 2003 - 2005 Envoy, 2003 - 2005 Trailblazer, 2003 H2