The Helios ETS 100 is a cross talk attenuator designed to minimize unwanted noise transmission in central ventilation systems. Made from high-quality polyurethane foam, it effectively reduces sound propagation between rooms. Designed for ducts with a nominal diameter of 100 mm, the ETS 100 is easy to install by simply inserting it into the duct behind the air valve. Ideal for improving acoustic comfort in residential and commercial ventilation setups.