PAC OS-4 OnStar Interface for GM 29-Bit LAN Vehicles: * Replaces factory radio in GM SUVs and trucks while retaining OnStar * Plug and play — no cutting or splicing into factory plug * OS-2/OS2-BOSE communicate directly with the OnStar module to prevent false triggering and eliminating unwanted audio noise * On-board amp will drive two 4W speakers in stereo * Use with the existing factory speakers or external speakers * GM 29-bit LAN vehicles