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.