I made this part to see if I could make a cheap flexible USB-powered LED (got mine at Dollar Tree) light have better throw. I was thinking maybe it could be used to make an inexpensive headlamp or work light. It snaps right into place, but the positioning of LED board isn't exact so they're not really at the focus of the parabola. My reflector print is pretty coarse, though, and at that size, I'm not sure how much it matters.
Printing at 0.1 or 0.05 mm layer height would definitely yield a more accurate parabolic surface.
Additional Print Settings:
Hatchbox Gold PLA
Painted reflector surface with chrome spray paint to increase reflection and opacity (light leak through plastic part).