Etymotic Research MicroPro™ ER-4P Consumer Headphones

The ER-4 MicroPro(tm) earphones from Etymotic are the next best thing to live music, with noise isolation far surpassing that of active-noise-reduction earphones. The ER-4's require no batteries, and can be plugged into any audio source. Their 20-25 dB of external noise exclusion allows you to hear the full dynamic range of recordings without having to play them at unnaturally high and unsafe levels.