At Woot, get this Matulsa 4" x 10" Register Booster Fan for $30. It's the best price we could find by $30.
It fits standard 4" x 10" vents and includes both a remote and built-in controls, with 10 speed settings and automatic temperature detection to help even out hot and cold spots in a room. Buy Now at Woot!
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Features Fits standard 4" x 10" register vents 10 adjustable fan speed settings Includes remote control plus built-in button controls Automatic temperature detection for heating & cooling modes Plug-and-play power cord for easy installation