Octasmart mattress topper has to be the worst buy ever,had in less than 4 months of use it has gone flat in the middle where my butt is.Im not a heavy person and bought it to relieve a painful back.I contacted the company with my complaint,the reply was rediculus,they wanted at least a dozen parts of evidence as to where the topper was used,the state of the surface it was on,what condition the area it covered ,photos of where it was in place etc etc.I felt this was a bit extreme so decided stupidly not to reply and put it down to my poor buying judgement.I would never use this company again very poor quality item.