Audiophile circuit breakers ?

No universal breaker, depends on load center. Square D industrial load centers are the best, IMO.

Do they fit in your panel? My basic German tells me these are only DIN-Rail mount and I don't know of any UL panels that accepts DIN breakers (they accept DIN rail devices such as TVSS's). As these appear to be Euro-standard devices, they may a) be illegal for use in the US, b) not be voltage compatible, or c) requires a Euro fuse/breaker box which may not be compatible with US codes. I'm curious as to what an electrician has to say. I, also, would have an interest in these.

Gs5556 -> I live in Europe, in Poland to be precise, so I have an DIN compatible breaker box as standard.

The voltage may not be an issue (if anything, the voltage in Europe is higher than in the US). However, the mounting standard may be another story.

In any case, I'm surprised that no one tried to market circuit breakers in the US yet.

At one time Rick at Virtual Dynamics sold cryo'ed breakers. Cryo'ed seemed to make a more relaxed presentation of the music. All the breakers, I believe were UL listed. I am not sure if they still sell them. Anyways, the difference in sound was from the cryo'ed treatment and not so much the breaker itself. Just guessing on the sound difference. Quick silver treatment also applied to the breaker and the bus bars also improves the sound. Be careful when working inside your breaker box.