Speaker wire isolators - Do they improve SQ?

In our beloved hobby we see at time all sort of gadgets and widgets and we ask ourselves, do the really improve SQ? This is the case of speaker wire isolators. More than often I am seeing on AG systems and even suggested by a reputable seller. My question to this forum is: Do they actually improve SQ ? It is noticeable? What material is used or makes this product workable?  Can I make them at home? I have seen some for sale at remarkable high price and I wonder if they are a cost effectively a sound investment? I have a carpeted floor. Please comment as you like.