The 9th & 10th Doctors' Sonic Screwdriver.
I printed an early version of this (one picture is included with backlighting from a flashlight for effect). I'm not entirely happy with that version and wanted to make some changes. The current model has been simplified a bit. This version is static and unmovable. The goal is ultimately to make a few simple modifications toward a new version.
This is modeled after various screen shots. The scale is a bit large so I suggest that you base your scale on the blue sphere at the tip of the screwdriver. The model dimension is 25mm diameter so if you buy a standard 25mm marble it will fit perfectly but the screwdriver will be quite large. I suggest finding a 16mm blue marble and scaling all parts to 0.64. Printing the sphere will therefore be unnecessary.
I sliced some of the parts based on surface color. It will make things easier to paint and then assemble after. I'll update this item when I finally print it and paint it.
29 Nov 2018: resliced the shaft components