All three of these appear on my map page on the Garmin site.

Product Key is 8 characters
Unlock Code is 25 characters
Code is 7 characters

I'm lost and would like a better understanding of what these are and what they do. Could someone please explain what these are used for and where? That is, which ones are used on the PC with Mapsource and which ones are used on the device itself.

Thank you!