we purchased this king for our camper because we had a 8 inch queen in our camper and LOVED IT!!! So we purchaaed another one because it is very comfortable!! We have a tempurpedic in our house, this is a great mattress for our camper. My husband lives in our camper during the week for work and he says while it's not a tempurpedic, its pretty close for a way better price point. Our daughter took our (3 yr old) queen and never wants to get out of bed lol.It took our king mattress well over 2 weeks to fully expand around the outter edges. Our queen took less than 24 hrs. So that part was weird but Amazon made it right!We are extremely impressed with this manufacturer!!! Will purchase from them again and recommend it.This was a lot thinner than I thought it would be. I've bought several memory foam mattresses before. This is more like a thick foam mattress topper more so than a mattress by itself.what I ended up doing was just placing this foam mattress over the old mattress and the bed sheets still fit perfectly over both of them.Very worth the price. Mattress is more comfortable than we had anticipated and after a day it's risen to it's advertised size. Would definitely buy again.Not sure where your manufacture is, but 4in doesn't equate to 6. I purchased this mattress in a jiffy as an extra for our metal platform bed. I had to put in on the floor because you could feel the metal through the foam. Had we had that additional 2" my guest would've actually been able to sleep on a bed.