GMOS04 Metra GM Onstar Retention Module $15399MSRP SKU: GMOS04 UPC: 86429115716 Vendor Part No: Compare Similar To see wholesale price Become a Dealer Already a dealer? Sign In Features GM ONSTAR Retention for all Premium Sound Systems Instruction's Click here to view the instruction manual Features Instruction's GM ONSTAR Retention for all Premium Sound Systems Click here to view the instruction manual