a medium firmness sprung core offers lumbar and muscular support, evenly distributed to promote healthy bone and muscle growth in their most important years of development. Above this is a comfort layer of comfortable smart-fibres, which actually wick away heat and moisture and have an open cell structure allowing a healthy airflow presence. All this and more keeps the mattress fresh and hygienic well into their later years, and for your peace of mind, all of Jay-Be's toddler mattresses come with a 5 year manufacturer guarantee.