The Sentinel D‑Box Twin Fan 250mm (Stock Ref: SENT250T) is a commercial-grade demand ventilation fan engineered for reliable airflow performance. It accommodates duct sizes from 100mm to 500mm, providing airflow from 0.001 to 1.3 m³/s and pressures up to 650 Pa. Equipped with energy-efficient EC/DC motors and a lockable isolator, the fan ensures safe, straightforward operation. Its Aluzinc construction allows for installation in both indoor and outdoor environments. Manufactured to BS EN ISO 9001 standards and performance-tested to BS848 Part 1 & 2, this unit delivers consistent, efficient ventilation for commercial applications.