I have the device to the left for $55 per month. I would like to know if I could purchase a hot spot that could hold the same phone number so the bill doesn't get higher? If so how far could I travel with that hot spot? Anywhere theirs tmóbile it will work?

Apparently Im prevented from using the square picture box to upload the picture of the 2 devices side by side but I'm sure someone is English comprehensive enough to know what I am asking without a photo upload.  Does the sim from the gateway have to get inserted into a hot spot device to use when travelling away from the gateway tower? Is that duable? Can home internet get taken out of the home with a mobile hot spot?