Hi Ilvtfly2, I own a 858 and I investigated the possibility of purchasing a Navionics Platinum card so I visited my local boat shop, phoned Humminbird in Sydney Australia and actually took my unit down to Navionics Sydney office. The guy at the boat shop who is very knowledgable and the boys at Navionics could not get the full functions out of the Platinum card and Humminbird Australia were not confident of total success using the 800 series combos also. But Greg has told me in a previous thread and a guy from Navionics on another forum that it all should work except Turboview. So I'm still confused about it all. I eventually went and bought a Gold card. Cheers Mark