The knobs scratch a bit against the metal casing, but it works as expected. The sound is a little muffled, but that goes for all attenuators. I'd wish the volume scale had been done a little different as I'm always trying to turn the volume knop a millimeter up and down to set the volume, as it very quickly gets quite loud. So a bit of fine tuning in the bottom would have been nice. However, it works well, sounds good, no problems.