We were only able to use it when we were in Spain, and come to find out from the Keepgo specialist who finally got it to work, they have different coverage agreements in different countries, so the network is spotty or may not work in some areas (possibly the issue we had in Denmark and UK)

If the fastest network is available it links to that.

With each country you enter I  needed to establish the proper network.

It looks like they only support 3G networks now, so please check with customer service if you're unsure

a T-Mobile data SIM and the Keepgo SIM.The AT&T SIM worked very well, was completely automatic and had 4G speeds, but was also by far the most expensive.