DKS DoorKing 1815-319 Card Holder DKProx LR RVM

DKS Doorking 1815-319 Card Holder DKProx LR RVM (rearview mirror). It's a small, unobtrusive item. The card should be placed on the side of the car closest to where the reader is positioned on the driveway. Usually inside the car in the lower or upper corner of the windshield or hanging from the rearview mirror. It works with the 1815-350.