A spring interior core offers excellent support and durability within a cot mattress. springs are often the preferred choice for a cot bed mattress because they are longer lasting and provide excellent postural support. the space within the spring lattice allows for increased airflow within the mattress helping to regulate your child's temperature and keeping the mattress fresh. the springs are linked double cone orthopaedic springs, which offer excellent spinal support and comfort. each spring core is encased within a high grade, dent resistant, orthopaedic foam, as well as an additional thick felt layer for added comfort and longevity.