Recommendation? propane tank to forge connection issue

[scarysamcary]

I recently replaced my 20lb tank (I know, I really should move to a larger tank), but I think I made the mistake of leaving a piece in the tank when I made the exchange. Now, my tank doesn't match up to my forge and I can't seem to find the right replacement piece.

If anyone could point me in the right direction or just tell me what to buy, I would really appreciate it. I have a fair amount of projects that I just can't get done without my forge.

 

[Stacy E. Apelt - Bladesmith]

That is a fitting to connect to a compressed gas tank ( looks like acetylene). You want a propane tank fitting.
Go to a welding or propane shop and get a POL fitting. Or, order one online.