Nut for the nose/"neck" thread of Dremel 3000 multitool.
Don't know what thread standard it is (if any), just measured, drew and printed. Seems to fit rather nice.
Might work with other models but don't know.

I use 1.2 mm shell, 30% infill (cubic), PETG, skirt, no supports, 0.2mm Z.

Model info:
Made in FreeCad with ThreadProfile plugin.
7 mm thick.
I will try to include FreeCad(0.17) file. If it wasn't, that's due to thingiverse not allowing me to attach file.

Thread:
Pitch: 2.17 mm, minor diameter 17.3 mm.

/Deformist