I actually purchased these as a replacement for an ExtremeRC F22 Fighter Jet. See my review for that particular product on Amazon. If you happened to buy one of those and you too have the issue of the blades randomly flying off the motor shaft, buy these. They are slightly smaller in diameter, but they work just fine and most importantly, they stay snug on the motor shaft. For $5, I would've hoped for more than just 4 blades though. Would've liked to see 8.