Details: Got mattress condensation? It's time to get rid of mattress funk caused by moisture condensing beneath your mattress. Den-Dry Mattress Underlay offers the ability to keep a mattress elevated enough to allow airflow. It's spun polymer and plastic enables bedding to stay elevated above the bulkhead, even with two humans sleeping on the mattress generating BTUs all night long. This creates a barrier that allows air to flow, keeping the mattress out of condensation's way. No more of that funky smell while making the bed. Underlays a Twin Bed.