In simplest terms, the loop goes around your neck and the small earpiece goes inside of your ear. It is important, however, to ensure that the loop is well concealed, otherwise it can totally give the game away. Wear a high collared shirt or blouse in order to hide the loop around your neck.
The earpiece itself is usually flesh coloured (different shades and skin colours are available), but even if it isn’t, the earpiece is so small that people are unlikely to even notice it.
The microphone needs to be positioned near to your mouth, but not so near that people can see it. Once again, a high collar will be of some service here, because you can place it underneath the collar line (spy earpiece microphones tend to be rather powerful for their size – but remember to test the whole setup first before you go into the field). If you happen to be wearing a tie, then so much the better, because the microphone can be easily clipped behind the tie (where it is very unlikely to be noticed).
Next, take the loop (making sure that it is under your clothing) and ensure that you can easily access the battery, beeper button and any other attached gadgets. You can run the battery straight into your pocket, provided your shirt is long enough, or, if you’re feeling particularly clever, you could even cut a small hole inside of your jeans pocket and thread the beeper/battery through the inside of both your shirt and your jeans (this will also work for your phone).
The hardest things to hide will be your attached cellphone or two-way radio. The cell can sit, quite happily, in your pocket (in fact, people generally expect you to be carrying one anyway), but the earpiece’s connection to the headphone socket must not be seen (keep it under your clothes, as discussed above). The two-way radio option is a little more difficult. Two-ways can be hidden on your belt (underneath loose-fitting garments), around your back (again, covered by clothing) or even strapped to your leg. It is definitely harder to hide a two-way, so it isn’t the ideal option for prolonged covert usage.
Finally, we advise you to check the whole thing out in the mirror first. Make sure that outside influences such as wind, rain, pushy crowds or actions such as running to catch a train are not going to expose your subtle setup. If you think you are too exposed, try different permutations on the advice provided, until you find something that works for you.