The Helios Fans ZLA 125 RS is a telescopic ventilation duct designed for use with the ZLA 125 system, adjustable between 260 mm and 500 mm to fit various wall thicknesses. Constructed from durable white polymer, it includes a 200 mm sound-insulating insert made from melamine resin foam to reduce noise transmission. The kit also comes with two structural protection covers, ensuring secure installation and long-term durability. This component enhances acoustic performance while supporting clean and efficient airflow in residential or commercial ventilation setups.