A step up from the SR125e, the Grado SR125e employs a state-of-the-art, closely matched drivers and cable design utilizing Ultra-High Purity, Long Crystal copper. To reduce resonant vibrations Grado Labs have developed a proprietary SpaceBlack Polycarbonate that is applied it to the internal housing in order to improve clarity. 

"There's really no doubt in my mind about that. I also believe that these headphones are great. Not just in terms of value or within a particular category of transducer. But great. Period. They deserve to be at the top of a very short list of headphones anybody would consider purchasing." — Head-Fi.