LAY-FOMM 40 is the newest innovation from the creator of LAYBRICK, LAYWOO-D3, and BendLay. LAY-FOMM 40 is a foamy material and is highly porous. LAY-FOMM 40 is part 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.
We recommend printing LAY-FOMM 40 between 220°-230°C. However, remember that each printer is slightly different so you may need to increase or decrease the temperature by 5°C until your print looks perfect!

Please read this article in 3ders.org for getting some backround.
http://www.3ders.org/articles/20131222-printing-porous-and-fibrous-3d-objects-with-new-filament-line-poro-lay.html