Up for sale is some old tank regs I have laying around. All of these should work fine. I'll describe them as best I can below. Let me know if you have any questions or want to see any better pictures.
Immortal Air #1 - some thread wear, gauge has a small crack in it but it still works, has the low pressure pack installed (those are $15 alone from IA)
Immortal Air #2 - like new condition, has the standard pressure pack in it (800 psi output I believe)
Ninja standard - barely used, like new condition, has the double oring bonnet and adjustable output
Immortal Air #1 - $18
Immortal Air #2 - $32
Ninja standard - $34