The Sentinel D‑Box Twin Fan 400mm (Stock Ref: SENT400T) is a robust and efficient ventilation unit engineered for commercial environments. Suitable for duct sizes between 100mm and 500mm, it delivers airflow from 0.001 to 1.3 m³/s with pressures up to 650 Pa. Powered by advanced EC/DC motors, this fan ensures maximum energy efficiency and reliability. A lockable isolator enhances operational safety, while the strong Aluzinc construction makes the unit suitable for both internal and external installation. Manufactured under BS EN ISO 9001 quality standards and performance-tested to BS848 Part 1 & 2, the Sentinel D‑Box Twin 400mm provides dependable demand-controlled ventilation for commercial applications.