I made the mistake of buying two of these pieces of junk. Unfortunately they were all that was available from the local poor excuse for a hobby shop. There is no knurling on the backplate. They give you a couple pieces of sandpaper to keep the prop from slipping. There is also no way to register the prop cutouts and screw holes in the spinner to the backplate. Other than that the shape was pretty good for a 1/12th scale Ki-61. I wasted my money; I hope you don't.