Amazon.com: beyerdynamic DT 770 PRO 80 Ohm Over-Ear Studio Headphones in Gray. Enclosed design, wired for professional recording and monitoring : Musical Instruments
Beyerdynamic DT770: EVERYTHING you should know (32, 80, 250 ohms) - YouTube
Welcome to the Reference Class – Beyerdynamic DT 770 PRO 80 Ohm Headphone Review - Major HiFi