Each duster has a 4 layer thickness of fleece. The best thing I've noticed about using these dusters is they don't flatten out like the disposable ones do, so they actually last longer. And don't forget the fact that they are washer and dryer safe (with out fabric softener)
My favorite part, though, is that every time you wash them the fleece gets a little bit better a picking up dust. The more I clean the better they do!
• Find it: Swiffer Washable Hand Duster Refill, Set of 2, You Pick the Color at MitsuyoDay