This is the Guardian Stabilization Expander from Eagle Tree Systems.

FEATURES: For use with the Eagle Tree Systems OSD Pro Expander
          Sensor based expander provides high degree of stabilization to fixed
            wing or elevon model airplanes
          Also provides an Artificial Horizon Indicator (AHI) on the OSD Pro
            screen
          Stabilization gain can be controlled by an extra knob on transmitter
            via the OSD Pro's Aux2 port allowing stabilization to be tuned or
            turned off during flights

INCLUDES: Guardian Stabilization Expander with Wire Lead

                                                                   jxs 01/05/12
                                                                         ir/jxs