I acquired these Even H1 headphones in pristine shape at a thrift. For a song.
They came with this inline "interactive" equalizer. It has software that has a program. A woman's voice directs you to respond with button push where you start to hear music it plays. Do this seven times for each ear. From this it equalize sound. The equalizer uses a TRRS plug. I assume intended for use with phones or Ipod type devices.
I ended up not using the equalizer. I think it sounds better as stand alone headphones to a headphone Amp. I bought cables with standard stereo TRS plug.
For enclosed headphones , they sound very nice.
Build quality is very nice. Wood or veneered body. All aluminium and stainless hardware.
I don't find any current presence of the manufacturer.