The ER4 series, made up of the ER4S, ER4P and ER4B have been Etymotic's top-of-the-line canal phone series since their introduction in 1991. The ER4S are specifically targeted towards audiophiles and professionals who desire the best quality sound possible, requiring a high quality dedicated headphone amplifier to be driven to their full potential. Utilizing rubber triflange or foam tips the ER4 series are designed for outside noise reduction, to further improve the listening experience. A good pick for those who desire high quality sound reproduction, yet also wish to listen in near silence, without the discomfort and risk of listening at high volume levels.
