Flexible filtering filling material consisting of pieces that are 100% open cell reticulated polyurethane foam. The pieces filter out the damp warm condition within the filling, haltering the proliferation of microorganisms, giving the product a more sanitary and longer life....http://www.google.es/patents/US7255917?utm_source=gb-gplus-sharePatente US7255917 - Reticulated open cell filling material
