Matrix is a good option if you are looking for a permanent international number --- Frequently travelling to UK, my bills were just flying off the roof and were getting too difficult to sustain. I had used Matrix sim cards for regular travels once or twice but was really relieved when i heard that they deal in permanent numbers as well. I got myself a fixed UK number and its been over 7 months now that i have this number. Convenience at its best. I don’t have to update my colleagues with a different number everytime i go there, and the retaining fee is also very less.