I made a mod on my Tello and it works well if l do say so. I bored some holes into the edge of the prop guard, x4 and then ran 2 stiff wires across the body and stuck into the holes, creating a bowed arch above the Tello. It only weighs 4 grams and the balance is good. It is Great for indoor flying when the craft is headed hopelessly to the ceiling. The Tello will bump into the celing and harmlessly bounce down a bit and stay aloft with everything intact.