dcfairfan 4x3 Inch Radon Mitigation System Kit, Quiet 260CFM Radon Mitigation Fan Inline Duct Fan IP67 Waterproof with soft joint and manometer, High Airflow Exhaust Fan for Indoor Outdoor 4 to 3 inch is up for auction in Tools & Home Improvement. The current bid is $2.50, 99% below the $169.00 MSRP, in Good Condition. This auction has ended — similar items appear in live auctions regularly.