You can use a 32GB SDHC. I have not tried with any larger than that. Same is true of the X20 too. Using a 32GB Micro SDHC in 550. Downside on the 710, from recollection is its only USB1.1 and not USB2 so it takes an age to transfer all the maps, so better to use a Card Reader.
Last edited by The Maverick; 3rd March 2011 at 15:27.