Why Do You Get Four?

"So I can communicate with Rey and Alice with this thing?" Klaus asked again, just to be sure. 

He hadn't been in contact with any of his friends for a long time now, and if this thing was just as Grey said it was, then he would be able to communicate with them whenever he wanted. They could even talk every hour! 

"Pretty much," Grey nodded. 

Oliver, who was already astounded by the tracking device Grey made, was even more shocked by this communication device. 

This was something recent, so he still didn't have any ideas about it, just like most of the people on the continent. With such a device, wouldn't they be able to quickly locate Chris, and anyone missing if said missing person has one of the tracking devices on them. 

Of course, this could also be used in a negative way to track down people and assassinate them.