BT 80B RF3 Junction box.
3 Way IDC connectors to 3 way screw. Internal use only.
Surpresses RF interference on the line & suitable for ADSL installations.
Same filter as fitted to the BT IPlate/BT Broadband Accelerator. Fit to eliminate small Repetative Electrical Impulse Noise (REIN) which can affect Broad Band ADSL lines.