I love the "loft " of this mattress pad.  I don't know if it's the bamboo or the rayon.  I just know that it increases the comfort level of any mattress.  It is pretty resistant to matting/flattening out.  My Cal King pad has to go to the laundry because it is huge and won't fit in my washing machine at home.  When I get it back, it is just like new.  Fluffy and comfortable.  Wayfair has been very helpful when items aren't readily available.  They track the item until it's available and email you immediately.  I've had great customer service from them.