This is a custom-designed 3D spinner set designed specifically for the Do-335 model from Rabid Models. The spinners are designed to work with 9×7 3-bladed props and prop adapters (not included but available from Rabid Models).
The front spinner (shown in the picture below) is acorn-shaped and has a cannon hole in the center. The rear spinner is the same diameter but is longer and conical shaped.
The set includes two spinners and two backplates. The cone snaps onto the backplate, so there is no hardware necessary other than a prop adapter. The backplate has a centering hole which must be enlarged to suit your application. The plastic spinners are paintable. The 3D plastic is somewhat “rough” but can be smoothed by using sandpaper (mount the spinner on a screw and spin it using a drill).