The LB Fans 14 Amp Single Phase 5 Step Auto Transformer (model SPM5140A) is a high-capacity speed controller designed for use in commercial ventilation systems. With five selectable speed steps, it enables precise adjustment of fan performance while maintaining low motor noise and preventing magnetic hum. The unit is equipped with an integrated ON/OFF switch for straightforward operation. As part of the LB Fans Controllers & Sensors range, this model provides reliable and efficient control, making it ideal for demanding ventilation applications.