The Bendix/King ED-551A Electronic Display unit functions as a Horizontal Situation Indicator (HSI), Attitude Director Indicator (ADI) or Multi Function Display (MFD) as set forth by the EFS-50 system. The EFS-50 system includes an ED-551A Display unit, SG-465 Symbol Generator and CP-467 as well as the optional Weather Radar that can be added. When the ED-551A is used as an ADI an inclinometer is mounted on the front panel. The ED-551A uses a five inch display format. The high resolution CRT displays converted X-Y axis deflection signals as well as red, green, and blue video signals from the SG-465.

The ED-551A is available with variations between yellow or blue light, black or gray bezel, high intensity resolution field (HIRF), and 5V or 28V lighting. The ED-551A does not have any front panel controls. The ED-551A operates up to 55,000 feet maximum altitude and -40°C to +55°C. The ED-551A is 5.27 inches wide, 4.92 inches high, 11.6 inches long with connector and weighing at 9.00 pounds with the rack.