Fuck if I know, all I know is you can sit next to a blender in a busy office full of crying babies and barking dogs while writing a dissertation on an electric typewriter and the person on the other end of the line would never be able to tell. Professional headsets (like in the $300-$500 range) are honestly pretty incredible. If these silicon valley offices are too noisy for a high end EOS to handle, or if they genuinely have that many people constantly talking all day to the point that it's a problem then they need to go back to the drawing board. Steno masks have their place but for anything a garden variety techbro is doing they're either performative bullshit or a lazy bandaid. I guaranfuckingtee bossman has no interest in putting one of these on.