These two parts are the motor attachment and spinner for the FMS P40 980mm. The compressor inside the motor attachment is designed to cool the electric motor during hot summer months. I recommend printing with PETG or a material with high heat resisitance. From my testing, PLA will melt if the motor is continuously run for more than 5 minutes at +50% power setting. The infill shouldn't be less than %10 percent as the hub and rest of the parts need to take some load of the nut and screen. Enjoy flying with these cheaper nose cone. No more worry about damage to the nose. -The propeller can be found on my page as well!