This is a 1mm thin diffuser to spread the light out from a tealight within the Huntrix light stick (designed by Starklabs3d). You can find the original full light stick design here: [https://makerworld.com/en/models/1674298-v2-kpop-demon-hunters-huntrix-light-wand#profileId-1823255](https://makerworld.com/en/models/1674298-v2-kpop-demon-hunters-huntrix-light-wand#profileId-1823255)

I found this did a good job of hiding the direct light and making the whole thing light up better. Thanks to Starklabs3d for the original design, it's really good. 

To install, simply push in behind before you install the thin coloured part with the stylised ‘H’ on it.