Divans are simply boxes on wheels so they can be easily moved or boxes on legs so there is storage underneath. Sprung edge divans have coils or springs set on a frame. These are the most expensive style. Platform divans have a hardboard top and are quite firm. Firm edge divans are made with small durable springs in a wood frame. Flexible slatted divans are crafted with bendable wood creating a slight bounciness. The slat tension can be adjusted as needed on these flexible slatted beds.