... .Smooth Surface3.no toxic.durable in water ,could filter air,dustExtruded polythylene foam could stand some press ,closed cell ... ,good elasticiry ,no toxic.durable in water ,could filter air,dust.1 .pu foam material2, reticulated, mesh,10ppi-60ppi ... ,3 good resilient, good air permeability (95%) Tensile strength kpa ≤ 100 elongation percentage % ≤ ...