In-Ear Monitors (IEMs), is a type of headphone designed to be partially inserted into a user’s ear canal by using form-fitting tips often made by a range materials such as rubber, soft plastic, silicon, and more. It’s also common to purchase custom molded tips to fit your ear canal. This typically offers the best results in comfort and noise isolation.
You may notice musicians typically wearing an IEM during a live performance. This is to listen to a custom set of instruments.
Other names for IEMs are In-Ear-Canalphone, canalphone, or ear-canal headphone. People believe the acronym IEM became the popular replacement for canalphones with the iPod generation.
IEMs are sometimes mistakenly called earbuds. The main difference being earbuds are worn in the opening of the ear. They are not designed to sit in the ear canal.