My uncle who does audio installations showed me these but I didn't ask what they were. They had three little letters on them but I did not pay attention to them(I just wanted to listen
). He also had a pair of Shure E1s with him. I prefer the sound of the shures by far. I found the senns very dark sounding and the shures seemed to be more neutral and detailed. I also found the shures way more comfortable and easier to insert. Due to the senns warmer sound with less forward treble I think they would be less fatiguing however I did not listen that long(I was busy listening to the E1s).
Hopefully someone else can chime in with some more info.