cozzivita 4 x12 in ultra quiet register booster fan - air vent fan booster with smart thermostat to fast heating and cooling room, white?vent size : 5.71'' x 13.78''? 4 x12 white is up for auction in Tools & Home Improvement. The current bid is $6.00, 90% below the $63.00 MSRP, in Good Condition. This auction has ended — similar items appear in live auctions regularly.