Radio Communications
This is CIA, KGB, FBI, Secret Service, MI5 stuff. Well, it was until the commercial market caught up and made it inexpensive and freely available to anyone with a PayPal account. This technology has been used for years with great success. Police, military, private detectives, and security details have used these kinds of products for decades. But they’re not the only ones, so have faith healers like Peter Popoff, who led followers to believe he had a “God given” ability to supernaturally divine audience member’s addresses and specific illnesses. But it was later discovered that his wife Elizabeth was feeding him the information covertly.
The best kinds out there on the market are the covert “spy” inductive earpieces produced, like a lot of other things, in China. But there are some quality producers in Europe and Russia too. Just about any “spy” store online or off will have access to something like this. Normally, a set includes a flesh-colored earpiece, which fits pretty deep into the ear canal, a receiver unit that may be built into something like a wallet or simply be in a neck loop, and the transmitter. Some kits come with a radio (walkie talkie), and others are made to connect to a cell phone, or anything else with a mini-jack like an MP3 player, et cetra. The most recent versions aren’t radio frequency (RF) based, but use Blue Tooth instead. Those are great for connecting to a mobile phone, which could be left on a call and simply put in your pocket or left face down on a table. Since the earpieces are so small, nobody ever sees them.