It is important to remember that the Serial Number and PIN that is engraved on the back of an each ID with Online Profile will be engraved with its own unique Serial Number and PIN combination. Doing this has several advantages. First, it's important to know that you can register multiple IDs to the same Emergency Response Profile (ERP) - eliminating the need to maintain different ERPs. Second, yearly membership fees for the Emergency Response System are based on the number of ERPs you have - not the number of Interactive IDs you have. This means that you only pay one yearly membership fee for each ERP - regardless of how many Interactive IDs are registered to the ERP. Third, you get six FREE months of membership for each Interactive ID you register. So, if you register two Interactive IDs to one profile, you'll receive a full FREE year of membership. Fourth, and most important, if you lose one of your Interactive IDs, you'll only have to report the missing ID as "Lost or Stolen." If all of your IDs had the same Serial and PIN, and you lost one, all of your IDs would become inactive. We had some pretty smart people develop the Emergency Response System. They thought of nearly everything. So, simply go to www.RoadID.com and begin building your new Road ID. We will automatically assign a unique Serial Number and PIN for you.