Would like to get tips on selling RFID labels

What is the difference in the antennas in the RFID label? There are so many to choose from. Does anyone have advice as to the best way to approach clients when they begin asking about RFID labels?

For example, in talking with one client, after I wondered about the inlays, I learned they use Printronix printers and I guess there are many less inlays relevant to that. We sell all sorts of printers, scanners and supplies. As RFID comes up more frequently, the more I know, the better. And I figure we all have to help each other for us to succeed.