Compact or HPQ filters are mini-pleat filters assembled on a polyurethane frame. The glass fibre filter medium is made with a “wet-laid paper technique” that guarantees high dust retention effectiveness and constant filter efficiency. HPQ filter is classified as ePM1 80%, ePM1 55%, ePM2,5 55% in compliance with ISO 16890 and E12, E11, E10 in compliance with EN1822.