Like many of you I bought these blades to replace my original blades which I had damaged but had no idea what they were. These are different from the blades that came with the drone. I'm glad I bought two sets as these blades can't be mixed with the old ones. I replaced all 4 blades and did a test flight. These things are really quiet. Like a loud whisper softly. Noise reduction by 30-40% IMO. Significant. And I swear my drone grips are better now. I don't know how or why, but now she's slipping. I love this prop. Do yourself a favor and simply order 4 kits: two for your original EVO II propeller and two as a backup spare.