You can buy them in Mexico, but please be warned that they are illegal in the US. You can go to jail and lose a lot of money. Most of the time people do not know what has happened. There use by some Government agencies has happen and will happen. If a bomb could be set off by a cell phone jammers have been used in limited cases. They have also been used to drop people off cell towers , so critical government agencies can communicate. It happens during major events like bombings and plane crashes, that so many people use their cell phones that it jams up cell activity, using a jammer for a second drops peoples calls so Police and other emergency response can get on line. So if telling family that you are ok, do it fast, it is possible you will be dropped.
from CTI Consulting http://ift.tt/1TuDahr