As everyone else bought an expensive bed , were unsure about a topper as would not be able to turn mattress and had had a previous poor experience . We were reassured by a very convincing con artist and asted even more money on the extended guarantee. Mattress now sagging, hurting backs and we almost roll out of bed with large hump in the middle. Activated our warranty , man with the string arrived, could see the problem but said he would do the tests but we had no chance as 3.5cm sag was permissible. Please everyone do not use this company and be aware the guarantee is worthless