In simple, Jammer is a signal blocking device, which transmits radio waves by creating interference on the same frequency range of the device that one needs to block. The disadvantage of mobile jammers is that the transmission of the jamming signal is prohibited by law in many countries. Jammers come in a variety of styles and strengths.
The use of a cell phone jammer, GPS blocker, or other signal jamming device designed to intentionally block the devices like phone, drone, etc.