The ER-4Ps are the Etymotic Research In-Ear monitors that fit into the ear canals with either flanged soft plastic eartips or foam eartips. The plastic eartips can be cleaned and reused. The ER-4Ps have enhanced bass and higher sensitivity. ER-4Ps can be used with portable CD, MP3, DVD and other players without requiring an additional amplifier. The higher sensitivity and enhanced bass of the ER-4P have made it the most popular earphone for most uses.

Includes a review of the Shure and Etymotic In-Ear Monitors and the HeadRoom Portable Amplifier!