ADS B out transceiver. This was removed from a Cessna182 N during a panel upgrade. I purchased the plane in 2017 and installed a Garmin with ADS B in and out shortly after purchasing the plane, and never used this unit which was installed by the previous owner. I do not know if it is functional, but date codes suggest it was installed in April 2017 ( I purchased the plane in November2017), and I have no reason to believe it is not in working order.