High Resolution Audio (Hi-Res) plays your music in its purest form
Acoustic open-back architecture for pristine audio fidelity
Dedicated cable management clip for tangle-free ease
Deluxe memory foam earpads for long-wearing comfort
Breathable velour cushions to help dispel pressure and heat
Seems to be the cheapest they've ever been (NEW) at Amazon according to the three wise camels: http://uk.camelcamelcamel.com/Philips-X2-00-Fidelio-Headphone-Black/product/B00MRUPSHQ?context=browse
You might notice reviews talking about poor build quality but these issues have now been ironed out.
Price has dropped again. Dispatched within two months. Seems they are going out quicker though.