HE-500 with newer style Hifiman headband (also no model number on this headband makes it more sleek). Whilst I was changing the cups over, I broke one of the SMC connectors, and I had some new ones but also some mono 3.5mm sockets and decided that they were a perfect fit so now they have 3.5mm sockets installed. Currently with HM5 angled pleather but they are lacking some sparkle so need to pad roll a little.
Thanks for this guide, I made one of the holes a tiny bit too big so there was a little play, so what I did was put a ring of heatshrink on the tab of the headband and that tightened it up. Overall very happy, these cups are a little dented and far from cosmetically mint, but it doesn't matter when they sound this good