Chemical resistance... what does that even mean???

I own the k712, they feel very airy in the vocals with a somewhat v shaped profile (spicy trebly with noticable mid bass bump), timbre in the mids is a bit wonky (hense airiness) But the best thing about these is the soundstage, it feels so damm wide, my friend says it reminds him the most of a speaker system and I have to agree. And the detail/imaging is spot on, everything feels crisp and pin point precise