The LB Fans 9 Amp Single Phase 5 Step Auto Transformer (model SPM5090A) is designed to provide reliable control of fan speeds in commercial ventilation systems. Offering five adjustable speed settings, it allows precise management of airflow while keeping motor noise low and avoiding magnetic hum. For ease of use, the controller includes a built-in ON/OFF switch. As part of the LB Fans Controllers & Sensors range, this model combines dependable performance with practical design, making it a suitable choice for various ventilation applications.