https://www.amazon.com/TAISHER-Stainless-Degree-Barstock-Fitting/dp/B092VLCL6J

But there is one other fitting between that and the regulator mentioned above “ 1/4” MNPT to 1/8” MNPT - $8.99”

The 90 degree bend makes this thing super compact which is great for backpacks, but it means you can’t use it on the larger tanks, only the 580-630g tanks.