The Helios ELF-ALB 50/30 M5 is a replacement filter set designed specifically for ALB fresh air boxes. Each filter is constructed from high-quality synthetic fleece supported by a durable fiberglass frame, ensuring reliable filtration performance. These filters are tested in accordance with DIN EN ISO 16890 standards and are rated ISO ePM10 70%, equivalent to filter class M5. Supplied as a pack of three, they provide an effective solution for maintaining optimal air quality in Helios ventilation systems.