An open-pore, flexible polyurethane foam on a polyether/polyester base.

PPI (pores per inch) indicates the number of cells in the foam per inch.

The standard range is 10-80 PPI. PPI 10 has large cells and is completely open, while PPI 80 has small cells, is more dense, and has a lower air flow.

PPI filtration foam is also available on a polyester - or polyether basis.

PPI filtration foam on a polyester base should not be used in proximity to water or other humid surroundings, as there is otherwise a risk of decomposition. However, PPI filtration foam on a polyether base is suitable for applications in humid environments or water filtering.

Applications
For filtering dust, water vapor, drifting snow etc., or as a filter and lining in loudspeakers.