These are 2 pcs of Revox Pro Servo Extension 22AWG Cable Wire 50Cm with Futaba J Connectors.
This extension goes between the receiver and the servo to make the wire longer. 
On one end of the wire is a male "J" connector and on the other end of the wire is a female "J" connector.
Wire Gauge: 22AWG
Wire Color Codes:
Black: Negative
Red: Positive
White: Signal (polarity tab is on the signal side)