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This is NOT a Propeller(r/videos)
It is a sensor that senses rotation. When the plane is rotated, it automatically applies corrective action on the appropriate control surfaces (assuming you set it up correctly). The unit also lets pilot control inputs through. This instantaneous reaction helps to smoothen things out.
This is the one that I used: www.amazon.com/JMT-P1-gyro-Controller-Stabilizer-A…