Works perfect with DT770Pro !
My previous adapter that was included with headphones, started to have weird error - whenever it was screwed till the end, I heard only mono signal - so to get the stereo, adapter needed to be 'loose', not screw till the end. I've ordered this M5 and works perfectly, when screwed tightly. Totally recommend. Just make sure it fits into your cans, as Beyer changed some stuff during years with connector dimension (jack plug)!