Warn Industries has taken MOSFET (Metal-Oxide-Semiconductor Field-Effect-Transistor) technology and put it to work for serious off-roaders. The 9.5si MOSFET control module eliminates the solenoid pack and its electro-mechanical functions. Operating temperatures from -40°F to +180°F won't faze it. Voltage drop to the winch is minimal for more efficient operation and low heat gain. With it's extreme sealing system and the 12.5 lb aluminum die-cast body, the 9.5si is the winch for the really serious user who requires the ultimate in reliability, durability and control.