It is loosely inspired by the following model: https://www.printables.com/model/1659597-ultraglow-keychain-lamp however the author does not allow Remixes - so here it is, a stand alone model, redesigned ground up.

Why the redesign? First of all - I hate glueing anything 3D printed. For this model - no glue is required. The cap is screwed into the body. I was also concerned about long-term resistance to damage of the very fine body net as well as ease of printing it. Hence the following design changes:

- the pattern is honeycomb (which I love) and is thicker thus sturdier (in exchange of exposing less of the glow material but I believe it is a good compromise). Also, printing this one is significantly easier.
- the key ring loop is reversed: instead of sticking out it is modelled into the cap. Again: not only it prints easier but is a lot more sturdier = very resistant to damage/separating along layers thus losing entire thing. Compromise is you still need to hang it somehow - easiest (but of course not niciest) is a cable tie.

While the housing is printed with regular 0.4 nozzle (in my case from fast PLA+ and .25 layer) the Ultraglow insert is recommended to be printed with 0.6 hardened nozzle. It is designed with 3 mm thickness to provide more material to glow at the same time sparing the (expensive) ultraglow material, i.e. not printing it solid. 

The same stl model for the glow insert can be printed in vase mode, i.e. one layer thick. I printed with 0.25 thickness without any issues. Just take the GlowFill.stl and either print as is (=3mm thick wall) and give it a couple of perimeters or switch to a vase mode, in which case only the outer-most perimeter is printed. The difference in glow intensity is notable however even the one layer vase mode infill glows just fine.

Completely optional are Core inserts - there are two - one for standard Glow fill and one for a Glow fill printed in vase mode. Print from PLA for sturdier design. Print from Ultraglow if you insist on maximum glowing infill. Or leave empty - as a hollow for a secret message perhaps?

Finally there are two version of the casing: a tighter one and one printed a bit looser - depends on how you print the glowing infill (layer thickness etc.). I suggest to start with a loose one (definitely for 3mm glow fill) and only switch to a tight one if the filling rattles inside. From my experience even the looser one is pretty tight, the tight one suits the vase mode printed infill only.

Print without any supports. Also no brims or skirts were needed on my trusted Mk4S. The cap is printed upside down. The casing body straight up with the threaded end on top. 

Publishing a picture of your print will make me happy. Let me know in the comments if you would be interested in a longer version, e.g. inserting a banknote into the cavity?