What we have here is a Heavy Duty Futaba J-Series 1000mm Servo Extension. This extension goes between the receiver and the servo to make the wire longer. On one end of the wire is a male connector and on the other end of the wire is a female connector.
Connectors slide snugly together to guard against vibrating loose. Heavy 20-gauge wire handles higher current loads with ease.
One Heavy Duty Futaba J-Series 1000mm Servo Extension
Wire Gauge: 20 Length: 38-5/8" (1000mm) (between terminal ends) Wire Color Codes- Black: negative Red: positive White: signal (polarity tab is on the signal side)