Will darken the mirror automatically when the cars behind you or on the side is too bright or with high bean as well as cars from opposite direction with to bright headlight or high bean. It will then clears back to normal when the brightness reduce from cars in front or behind automatically. Dealership will cost over a few hundred dollars just for the mirror. The item "FACTORY OEM BMW 2014 2018 i3 Auto Dim Rear View Mirror COMPASS HOMELINK" is in sale since Friday, January 3, 2020. This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts\Interior\Mirrors".The seller is "auctiondealonline" and is located in Sunnyvale, California. This item can be shipped worldwide.