Bought this top of the line, $3, 000, mattress from Kingsdown and after 4 weeks started sagging in the middle. Called to complain, they send a kit that measures sagging with out load and they said the mattress is performing as designed with up to 2 inches sagging being normal after the 1st month. Called again and someone came to the house, it was a subcontractor called Mattress Marshals, and he said the materials are shifting. Again the factory sent a letter stating the mattress is performing as designed. Noe I have a 20 year useless warranty, back pain, unable to sleep in that mattress. Before that I had an excellent mattress, with springs, and was perfect, until I got married and wife wanted a kings size mattress. I wished I went to the normal cheaper ones. This company is a scam and rip off with this warranty.