1. For Flip special propeller. Lower noise, precision dynamic balance inspection, higher thrust-to-weight ratio, and more powerful pull for the craft. 2. Please follow the tips on the propeller bag to install the propeller on the correct arm. 3. When replacing the paddles, you need to use the paddles in the same package, do not mix them with the paddles in other packages. 4. Specially designed for Flip, these propellers are engineered to produce less noise and enhance aerodynamic efficiency. 5. Each propeller undergoes precise dynamic balancing tests to powerful thrust and optimal performance. Diameter x Pitch: 4.0 x 2.2 inches Note: 2 blades with 2 screws form 1 blade, 2 blades form 1 pair of propellers. Due to different batches, there may be differences in product appearance, color, and printed text, which not affect the use. Colour: Material:ABS Package Contents: 1 * Propeller Kit Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.