I have this memory foam topper  on two beds one a single one a king size and both in the 5cm depth. Its a good quality foam and having a removable washable cover makes it more hygienic. Id advise airing it for a few days before putting on the cover and using it on a bed- memory foam can have a slightly unpleasant smell out of the packing(it soons passes). I have problems with my muscles and joints, so having this supportive, but comfortable, topper means a better night and less painful morning. I have a good quality new mattress, but this topper still improved my bed. I take it for granted now, until I sleep on a bed without it and realise just what a difference it makes!