| EARPHONE CONTROLLING AGENCY | WECO |
| EARPHONE ELEMENT TYPE | MAGNETIC |
| EARPHONE IDENTIFYING NUMBER | HC3 /FIIN 248-2971/ TYPE NO. |
| EARPHONE IMPEDANCE RATING | 300.0 OHMS NOMINAL |
| EARPHONE QUANTITY | 1 |
| CONNECTOR IDENTIFYING NUMBER | U-77/U /FIIN 256-3807/ TYPE NO. |
| CONNECTOR TO JUNCTION CORD LENGTH | 3.500 FEET |
| CONNECTOR CONTROLLING AGENCY | JCENS |
| CONTROLLING AGENCY | WECO |
| FREQUENCY RATING | 0.2 KILOHERTZ MINIMUM AND 3.0 KILOHERTZ MAXIMUM |
| IDENTIFYING NUMBER | N1 /FIIN 242-6558 TYPE NO. |
| IMPEDANCE RATING | 40.0 OHMS NOMINAL |
| OUTPUT LEVEL RATING | 38 DB ABOVE 1 MV |
| MICROPHONE ELEMENT TYPE | CARBON |
| MICROPHONE MOUNTING FACILITY | SHAFT |
| MOUNTING METHOD | SUSPENDED ON HEADBAND EARPHONE |
| NONDEFINITIVE SPEC/STD DATA | H-81/U PART |
| OPERATING CURRENT RATING | 85.0 MILLIAMPERES NOMINAL |