Dayton 3C188C 240V Motorized Damper Shutter w/ Spring Return. This motorized damper. features wide center-pivoted blades for a full 90 degree rotation with parallel blade action. This damper can be used for exhaust or supply applications and can be mounted in a vertical or horizontal position. The 3C188C 240V Motorized Damper motor is mounted and factory installed for 240 volt power open / spring close operation.