A 10 cm topper that goes on top of the mattress you already have. It is built in three layers: gel memory foam with a wave profile on the summer side, 4 cm of firm support foam in the middle that does not sag, and memory foam on the winter side. The memory fills the gap under the lower back and is cut into 7 zones, softer where the shoulders rest and firmer under the hips, so your back stays on its natural line whether you sleep on your back or your side. Between the waves the air moves, and a 3D mesh band around the four sides lets the edges breathe too. The cover has a mesh summer side and a quilted winter side treated with aloe vera, a water-repellent, stain-resistant finish and a waterproof membrane underneath, so spills stay on the surface and the mattress below stays dry. It unzips on three sides and goes in the washing machine at 40 °C. A non-slip base and four wide reinforced corner straps keep it in place, on a bed or a sofa bed. It arrives rolled and vacuum-packed with two memory foam neck pillows and a carry bag. Same price in all 10 sizes, from single 90×190 to king size 200×200; we confirm the size with you on the phone before shipping.