What navigation disc is needed for a 2005 cadillac escalade?

I have a 2005 Cadillac Escalade but it is missing the navigation disc. I've found multiple discs on ebay and want to purchase one but I'm not sure which disc will work. Does anyone know which disc came with it? I'd like to get the most updated version but want to be sure its compatible and will definately work before I spend the money. Thanks!|||You can try asking the dealer . Or try the Navtech web site.