If you are talking about the old G charts good luck. I have given up. The micro's are even harder to come by. I have a practically brand new 180 gpsmap and no chip. A waste of a one time 700 dollar unit. Still can't understand how they got away with that one

. Just stopped making them and went to a better chip and screw everyone who happened to have the older model and paid 700 bucks for it.

Paul