Make sure the size of your mattress first: the mattress topper must have the same size (a mattress 90x200cm will welcome a mattress pad 90x200cm). We are able to make the comfort synthetic mattress toppers and prestige prestige synthetic mattress overlay according to the dimensions of your choice, within 10 days maximum. Custom products can not be returned or exchanged. In order to fix them durably, the synthetic mattress toppers are provided with elastics at each corner. The natural mattress toppers stand alone thanks to their greater weight. If you choose a 6cm thick down mattress topper, be sure to check the size of your fitted sheets to make sure they cover the thickness of the mattress and the mattress topper. The mattress overlay 90x200cm will bring a complement of comfort to a firm or medium mattress, and will ensure a reception of unequaled softness. It is the ideal companion of a mattress of good maintenance. All those who have tested our mattress topper in a luxury hotel recognize that it is incomparable! Remember, however, that it will not give a second life to your mattress... When it comes to maintenance, the natural comfort mattress topper is not washable in a domestic machine or in a dyer's shop. We must think of protecting it as a mattress, with the appropriate protective cover that we offer. In general, do not forget to protect your bedding with a protection, fleece or other, which you usually use.