Durablow MFB SC03A Fireplace Stove Blower Fan Variable Rheostat Speed On/Off Switch Ctrl Variable Speed Electric Motor Control for fireplace fan / fireplace blower kit This is a rheostat, or Speed Control for your fireplace blower fan. It allows you to control the speed of any fan. Applications: Fans, Blowers, Fireplace Blowers. Wires measure 6" long (can be cut and peeled off). D-Shaped Stem measures 1/4" Technical Details: Volts 120; Frequency (hertz) 60; MAX Consumption (watts) 300; Rheostat, UL Approved.