It's your remote lock transceiver for the key fob. If you have the fobs you're golden. If not it's useless bc you can't reprogram it to work with another fob, and vice versa.
1966 109 5 door wagon 300Tdi "spermaceti fueled"
1994 RRC LeWiB "ruining the air behind me"
1968 2A 88
All my troubles are Rover