It stabilizes flight and protects safety in extreme propeller crash cases in which propellers will not smash into scattering pieces. The willow-shaped propellers are optimized repeatedly to least resistance, highest efficiency and smallest noise. The foldable design and foolproof installation make highly -friendly. Classic quick release design Quieter and flight Dimensions: 45x15x117mm 1. high toughness materials for high aerodynamic efficiency, 2. low power consumption and high endurance, 3. Classic quick release design, press and rotate, quick installation in one second. Applicable models: for II, II Pro Color: black Material: PC Package Contents: 2 pair Propeller 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 a little different from the real thing. The measurement allowed error is +/- 1-3cm.