This is the Futaba CA-RVIN-700 External Voltage Input Cable.
FEATURES: Used to connect a Futaba telemetry equipped receiver to an extra
INCLUDES: Cable, Fuse, Heat Shrink Tube and Instructions
SPECS: Length: 27.5" (698mm)
COMMENTS: This voltage cable plugs into the R7008SB next to the antenna.
This measures the external voltage, such as the battery that is
running a motor.
The voltage will be displayed in the transmitter as
Maximum voltage is 70 volts.