The S4-34760-28 from Gent is a 2.8 Venturi Tube for use with Duct Smoke Sensors. This device shall employ a molded plastic housing with a clear viewing window and metal probes (Gent 2.8M Venturi Tube) to pick up smoke in ventilation ducts. The housing shall provide a smoke entry test point and an airflow indication. Depending on the risk and sensitivity levels required, the sensor to be fitted shall be selected from the full range of sensors available and not factory fitted. This unit is particularly suitable for sensing smoke particles in ducting which is likely to be in large quantity and flowing fairly quickly.