The Elta APK400/003 ancillary pack is a complete accessory kit tailored for 400mm ventilation systems. It includes four anti-vibration mounts to reduce noise and vibration, two flexible connectors for safe and adaptable duct connections, two matching flanges for proper sealing, and two mounting feet to ensure stable support. This pack is ideal for simplifying installation while enhancing the performance and reliability of HVAC systems in commercial or industrial settings.