The Etymotic ER4XR is an earphone for music lovers who want uncompromising accuracy in the mid and high frequencies along with extra presence at the low end of the frequency range. The ER4XR delivers very accurate sound in all frequency ranges combined with high performance. Channel balance is tuned to a very good 1dB for frequencies from 100 Hz to 10 kHz. The ER4XR in the slim aluminum sound body with laser refined surface is lightweight and comfortable to wear. New unlike previous models, the ER4XR comes with a replaceable headphone cable that can be easily replaced when needed. Outside noise is shielded by up to 35 - 42 dB (depending on the attachment used), so you can enjoy your music undisturbed even in noisy environments.