Up for your consideration is Futaba GY611 + JR DS8700G digital fast tail servo R/C Heli Tail Rotor Gyro System

Manual is provided on CD

No original packaging is provided

GY611 Gyro Features:

Adds a new dimension of control for larger-sized helis.

• A super narrow pulse (760µs) drive system greatly improves servo response; high-speed processing boosts gyro response.
  

• The high-resolution 12-bit Analog to Digital accurately converts the sensor output to a digital signal.
  

• Newest generation SMM (Silicon Micro Machine) technology and a low-back aeroform case enhance vibration resistance and neutral characteristic.
  

• The GY611's highly precise angular velocity sensor allows the AVCS to perform even better, minimizing rudder neutral position drift and eliminating the need to trim the rudder during flight.

GY611 Ratings:
Yaw-axis stabilizer for helicopter (rate gyro)
Display device: 8-character dot matrix liquid crystal display
Operating voltage range: DC 3.8V to 6.0V
Current drain: 70mA (@5.0V, including sensor)
Dimensions: 57 x 32 x 15 mm (amp), 30 x 30 x 18 mm (sensor)
Weight: 34 g (amp) + 30g (sensor)