This product is designed to lay under a foam or inner-spring mattress. It is approx. 10mm thick. It is non-woolen, non-organic spring-like suspension designed to allow air to circulate between your mattress and the baseboard. The airflow enables the mattress to remain dry, preventing mould stains, moisture damp and musty smells, etc. It also keeps the baseboard dry and clean smelling. It does not sag. It is a fantastic product, equally at home in a boat, caravan, 4WD or RV. It uses up almost no room. Two sizes available: Helps keep mattress dry free from mildew. Single (2015 x 915mm) RAC430 Queen (2015 x 1600mm) RAC432 The product improves the comfort of roll-up swags and camping mattresses as well. It has other uses too. It can be used to line shelves to prevent precious items from rattling or breaking on long trips. It is cut easily with a pair of stout scissors.