... used in insole for medium and top grade shoes, case, sport equipment etc. Advantage: washable, eco-friendly, breathable, durable, ... equipment, can product various shape of foams. 2.40ppi Air Filter Foam detail:1)Material: PU (polyurethane)2)Aperture: ... acid-resistant,alkalifast, Flexible,good tensile7)Use: filter dust, air, liquid, equipment filter etc. 40ppi Air Filter Foam 40ppi Air Filter Foam