Beyer DT990 Premium 250-Ohm Headphones – Alto Music
Amazon.com: beyerdynamic DT 990 Edition 600 Ohm Over-Ear-Stereo Headphones. Open design, wired, high-end for use with headphone amplifiers : Electronics
Modded Beyerdynamic DT 990 Premium Edition 250 ohm Open Studio Headphones | eBay