These joysticks have many uses including controlling the speed of two motors on two planes.

Joystyick details:

Size:               4 X 2.6 X 3.2CM
Control:         2 potentiometers for the 2 axes, 1 switch in z plane
Connector:   +5Vcc - GND - VRx - VRy - SW

These connections are well marked on the board next to the pins.