Small headphones in each ear. Also called "earbuds," earphones stay put by resting inside the ear or by being inserted slightly into the ear canal or with hooks that wrap around the ear. Another variation is an earphone that clips onto the earlobe.
High-quality earphones called "ear monitors" have been used by performers on stage to hear instruments as well as cues. They are also available with custom-molded inserts like hearing aids, which are called custom in ear monitors (CIEMs). See headphones
and mini-phone connector
Earbuds like these come standard with music players and smartphones. Although providing decent sound quality, higher-end earphones and especially headphones offer a better audio experience.
For professionals and serious music lovers, high-quality earphones deliver more listening enjoyment. These Munitio NINES use 9mm drivers, a 3-button control for Apple devices and small, medium and large tips for different size ear canals. (Image courtesy of BDA, Inc., www.munitio.com)
Employing the same process for hearing aids, these Custom Ear Monitors are made from impressions of the wearer's ears. The custom fit provides greater comfort and eliminates more ambient noise. (Image courtesy of Ultimate Ears, a division of Logitech, www.ultimateears.com)