The mattress cover is quilted with 100% polyester wadding removable zip off cover which can easily be removed and replaced for washing The inner core of high tensile Bonnelli springs are encased in dent resistant nursery foam to provide a fully supportive mattress The mattress is fully breathable and suitable for placing your baby in the feet to foot position Manufacturered without the use of Antimony, Phosphorous or Arsenic based fire retardant treatments The foundation for the study of infant deaths (FSIDS) recommends to parents that they adopt the feet to foot position when settling their baby down to sleep By placing babies towards the bottom of the cot and tucking them in carefully, ensuring that the sheets are no higher than shoulder level, will keep them from wriggling underneath the covers.