Also called an extension jumper, the female-male jumper wire makes an electrical connection between a protruding wire and a socket. These are generally used for adding length to a connection, helping a wire or pin fit into a socket where it simply isn't long enough. Some key examples of regular use include connecting an Ultrasonic Ranger or Accelerometer to an Arduino or breadboard, as an USR or Accelerometer generally has to be placed in a specific location on a device to fulfill its intended function, and a female-male jumper can draw the connection to the Arduino/breadboard even across longer distances.