Main body and moving part:
Has both internal and external threads, the body should be printed laying down as in the image, with the moving spikes placed inside the body so that it can be printed in place. The opening for the screw on the moving part should face the threaded opening of the body (of course).
Infill: 15-50%, anything will work more or less. No need to print 100% infill here, the forces will most likely not be that great.
Layer height: 0.2 - there are some clearances of 0.5 mm, so make sure your printer is dialed in before trying.
Supports: Can be printed without supports, but the rounded ends of the moving part will be deformed. I use Prusa Slic3r and just add supports to the very ends of that part so only the bottom of the rounded section gets support. No other support is needed.
The handle should be printed standing up, with the threaded rod going upwards
Layer height: 0.2
Supports: No support is needed