UH, your rite about the "t" version. I believe the map scale on the hunting GPS cards is1:24 vs the "t" which is at 1:100, so yes the cards are more detailed. I bought the 550 T, when it was on sale for the same price I could have got the regular and it came with the camera. So if it wasn't for that I probably wouldn't have gotten the T version either. But I will say it's nice to have the "T" version when you are passing through States that you don't have the card for.