This is a modified cable for HD650 and HD660s headphones. The original unbalanced cable was cut to 1.3m and replaced with a high-quality, well-known Toppra Sales 4.4mm 5-pole connector. The modification was done by PHONECABLE Seisakusho. The cable has been broken in for 150 hours. The modification cost 13,800 yen, which I think is a pretty good deal. The handling is as good as the original cable. This is recommended for those who are considering a cable replacement and don't want to risk a change in sound quality.