In-ear

Outside Ear Canal
The iPod’s earbuds are examples of this kind of headphone. Found most often with MP3 players, these headphones sit outside the ear canal without protruding directly inside. These are known for their convenience, inexpensiveness, and portability, but there are downsides, as well. These earbuds are more likely to fall out than ones that sit securely in the ear canal. In addition, these headphones aren’t capable of producing the same kind of dynamic range as full-sized headphones and canalphones, which causes many users to raise the volume of the music they’re listening to. At a higher volume, users are at more of a risk for hearing damage.

Canalphones
Canalphones are inserted directly into the ear canal, and have a similar portability to earbuds that sit outside the ear canal. A number of different sizes are often available to fit an individual’s ear comfortably. The padding around the earbud is most often made of silicone rubber, elastomer, or foam for comfort and noise reduction. These headphones aren’t for everyone, though – some find them to be overly invasive and don’t like how much ambient sound the earbuds block out. It’s best to try them out first before picking up a pair.

Who Should Use Them?
In ear headphones are great for sports enthusiasts – wearing on- or over-ear headphones while working out is often uncomfortable. They’re also great for portable music devices, and can be easily stored in a pocket or small purse. They’re not often great at cancelling noise, especially earbuds that sit outside the ear canal, so in-ear headphones aren’t best for frequent fliers.