... 3.density:according to the demand of customer PU filter foam1.material:PU2.color:black,white,yellow,blue,and ... so on.3.PPI: 10PPI to 60PPI,from large to small.4.density:according to the demand of ... .6.usge:we can make a variety of PU filter foam with different color,density,ppi as curtomer's ... demand.the filter foam can filtrate water,dust,oil,air,and so ...