The Helios ELFBR 100 G4 is an in-line air filter box designed for ventilation systems with circular duct connections. It features spigots on both ends equipped with double lip rubber seals to fit standard nominal duct sizes. The casing is constructed from galvanised sheet steel for durability. An access panel with a clamp enables simple and quick filter replacement. The filter media is made of synthetic fiber and classified as ISO Coarse 70% (G4). It is temperature resistant up to +100°C, fire resistant according to DIN 53438 F1, self-extinguishing, and can be regenerated 10 to 15 times. The filter offers a dust holding capacity of 122 g/m².