Marshall Major IV and now V - A feature I forgot about...

Yes, I had completely forgotten (until I watched this video review last night) about the feature that allows for the Major headsets to connect by Bluetooth to a source device and then run a cable to another headset by 3.5mm to share the music with a chum!

Bluetooth is getting very clever with this stuff and can often do the same thing wirelessly now, depending on the gear involved, but here's the old-school way! I'm not aware of any other OEM doing this with headphones.