It is a luxurious 12.5cm (5 inches) thickness and is composed of pocket springs individually wrapped in polyester fibre to move in line with baby and give maximum support to limbs. The sprung unit is encased in an environmentally friendly thermal bonded solid polyester fibre, helping to maintain the shape and prolong the lifespan of the mattress. The cover is an extra padded, pinsonic welded, extra padded quilt which is breathable and moisture resistant; it can be wiped clean and easily removed for washing. It is fully breathable and air permeable. The topper pad is included for extra comfort and allows body heat to be dissipated and lets air circulate around the baby's skin, thus preventing overheating. The cover is zipped around three sides to make it easier to remove and replace for washing. It is designed for placing your baby in the 'feet to foot' position.