The Helios BTV 125 shutter provides effective prevention of fire and smoke transmission within ventilation systems. It is designed for installation in ventilation shafts or ducting that serve as fire compartments, complying with the K90-4102 fire resistance standard. The shutter can be installed in spiral ducting or walls using the EH mounting sleeve. Maintenance-free and certified under approval No. Z‑41.3 – 694, the BTV 125 ensures dependable fire safety performance.