What's under the smooth cover of a lace sensor? Wikipedia does a very technical job of describing magnets and such but in a guitar newb's terms what's under that?? Could you switch out that cover for something else like a normal strat cover? Just wondering cause I saw a concert where clapton was using them and I was like "what's that?" and my guitarist goes "a lace sensor" so I searched it up and now I'm curious. But I digress.... Thanks in advance everyone!