A lavalier microphone, also called a lapel mic, lav, clip mic, body mic, collar mic and neck mic, is a miniature microphone. Small and discreet, their low-profile nature is what broadcasters and performers love the most. Gently tucked behind a button or hidden in a hairline, miniature lavalier microphones are the most unobtrusive technology on stage, on camera, on interview or on film.
You have probably seen lavalier mics used for television, theater, and public speaking applications. They are also commonly used in film production, although you will not be able to see them when used in this application as they are typically hidden in costumes.
These mics are very versatile; placement and mounting depends on which application the mic is being used for. In theater applications, lavs are often concealed in the performer's hair, forehead or even in their clothing. In television and public speaking applications, the lavalier will typically be clipped to the subject's clothing, usually on the tie, jacket or collar. As mentioned above, lavalier mics are very common in film applications, where they are hidden under clothing.