The Sentinel D‑Box Twin Fan 250mm (Stock Ref: SENT250T) is a commercial demand ventilation unit engineered for dependable airflow control. Suitable for duct sizes between 100mm and 500mm, it provides airflow from 0.001 to 1.3 m³/s and pressures up to 650 Pa. The fan features energy-saving EC/DC motors and a lockable isolator for safe, convenient operation. Its Aluzinc construction ensures durability and allows for both indoor and outdoor installation. Manufactured to BS EN ISO 9001 standards and performance-tested to BS848 Part 1 & 2, this unit delivers efficient, reliable ventilation for a wide range of commercial applications.