aquarium filter sponge, polyurethane foam materials . Various porosity can be available(10ppi-60ppi) Open cell& ... , 10ppi,15ppi,20ppi,25ppi,30ppi,35ppi,40ppi,etc.PU foam , Polyester foam, Polyether foam , top of quality ,reasonable price and great credit standing ... done many kinds of shape and size as clients' requirement White filter sponge for holding soap