Just few key features:
LED Array
An array of color LEDs that can be seen by more than 300ft, blink a Id code to visually identify the aircraft without any special equipment.
IMU and GPS
Basic sensors to capture and store telemetry data during the flight, so in case of a crash, it works as a black box.
Transponder
A radio transmitter (ADS-B, Xbee or Wifi) to send the Id code and last GPS position through radio, allowing automated identification and long-range detection.
Internal Battery
The standalone battery keeps the box on and transmitting for 1 hour even after a crash incident, helping the pilot to find the crash site.