Has your chosen phone network paid for exclusivity? If not, make it unlocked IMHO. I'm sorry Wisper, but I'd never buy an ebike locked into a deal with one phone network. Can your tracker be unlocked to use an alternative phone network? As a manufacturer, if locked in, your reputation is tied to that of the phone network... so it's worth making an unlocked GPS tracker. It would be convenient for me as a buyer if I could use any network I chose, shopping around for the best deal in the event that your chosen provider was too expensive, or provided poor services or support, now or in future. Also, a GPS tracker needn't need to use a data plan, it can work like a lot of other GPS trackers do: SMS only - it's even cheaper for your buyers. You could build a small sim card compartment into the bike, protected by a physical lock. Otherwise I would have to take the whole bike to a phone shop to try to get it unlocked, or post in to you enclosed in a large self-addressed stamped envelope to get it unlocked.