This "Y" harness is 12 inches overall. It has a 6 inch main lead with a universal male "S" type (also called JR) connector, and two 6 inch leads with female "S" type connectors. All of the servos we sell come with the male "S" type connector, and will fit this "Y" harness.
If you wish to plug in a servo with a Futaba "J" type male connector, you can simply shave off the little plastic ridge on one side of the "J" connector, and it will fit in the female connectors on this Y harness.
A "Y" harness is generally used to control two aileron servos with a single channel of the receiver.
This harness will plug into most receivers, including Futaba, JR, Spektrum, GWS, Cirrus, Blue Bird, Blue Arrow, Corona, Berg and Hitec.