The tail caps are led lighted. D.I.Y. Illuminated tailcap
The little thin glowing tubes are trit vials. https://www.fasttech.com/search?trit%20vials
They offer several different sizes with the most common used size is probably 1.5 mm x 6 mm.
The tubes can be glued in using UV active glue that’s transparent. https://www.fasttech.com/p/1285104
I usually wait for Fasttech to have some kind of 10 or 15% discount code sale, then I stock up. FastTech coupon codes...help keep members updated - #203 by Jassim
When ordering 3 or more of the same item it becomes a bulk discount and the discount code doesn’t work, so I place more than one order making sure not to get into the bulk order discount, only buying 2 of the same item and using the code. They also offer a few 5 packs that’s the better deal.
You can also make some 7 year glowing night sights for alot less than store bought sights.