LGT crystal chamber
thingiverse
You need to put this between grip and pommel, then put a kyber crystal inside. There's no led, so you need to buy crystal like this https://www.etsy.com/ca/listing/715145524/star-wars-lightsaber-kyber-crystal-100?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=kyber+crystal&ref=sr_gallery-1-1&bes=1&organic_search_click=1 You also need to glue this crystal to chamber. (That's my very first work, so i don't know if it works well)
Download Model from thingiverse
With this file you will be able to print LGT crystal chamber with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on LGT crystal chamber.