The Elta STDL500-3EC is a 500mm twin centrifugal box fan equipped with a 3‑phase EC motor for efficient, quiet airflow. Part of a series offering seven standard sizes from 125mm to 500mm, it delivers air volume flow rates up to 1.740 m³/s and static pressures up to 730 Pa. Suitable for operation at temperatures up to +60°C, the fan features a redesigned casing to enhance airflow and reduce specific fan power consumption. It includes an auto changeover panel as standard and is acoustically lined internally to minimize breakout noise. Configurable with optional spigot types, this model provides flexible installation and energy-efficient ventilation performance.