This is a good cheap gyro for beginners that are looking to take their game to the next level.  When you feel like you are ready to build your first 3D radio control helicopter, the Detrum GY48V is a great gyro to start off with.  Although the price may be cheap, the quality is not.  You will be amazed by how well this gyro holds.  Perfect for 3D and inverted flight.

Dimension (mm): 28*28*20
Digital proportional R/C system
Operating voltage: 4.8V~6V
Operating temperature: -10℃ ~ +45℃
Operating current: 80A

Functions:
1. Minimizes changes in an aircraft's attitude by wind etc
2. Angular acceleration commands used
3. Sensor vibration proofing
4. Simple sensitivity adjustment

The helicopter he’s flying is the Legend 450 and the gyro he’s using is GY48V Headlock Gyro which can be found here http://www.xheli.com/60p-dy-1017.html.  Notice the stability of the helicopter in this video and how close he gets to the ground flying it upside down and holding it at that level; that’s the work of the gyro.