This section includes overlays that are water-, fibre- or gel-filled or have a combination of fillings. They are placed on top of an existing mattress to offer support and/or pressure relief. They are thinner than mattresses. Some are designed to accommodate the size and weight of a heavier user.
Fibre-filled overlays are designed to provide comfort. They are filled with hollow core silicone-coated polyester fibre and have either a cotton, waterproof, or vapour permeable two-way stretch cover.
Gel overlays work on the principle that the user's weight is distributed over liquid or solid gel. Because the gel is able to conform to the user's body shape, the pressure is evenly distributed over the whole area. Gel conducts heat away from the user, making the mattress cool to lie on.