Lay-Fomm 40 is a foamy material and is highly porous. Lay-Fomm is printable with all standard home 3D printers. Lay-Fomm 40 is made from rubber-elastomeric polymer and part PVA. Once you rinse this material in water only the rubber polymer remains as your micro-porous and flexible object. Lay-Fomm 40 is slightly softer than Lay-Fomm 60.