I got it
Here .
However, it shows out of stock, but at the link there are alternatives . . . just make sure the "pipe" size is correct. BTW, some earlier posts, by others, listed an aluminum coupling to use. I ordered that too, but had to cut one end off to use. Then I found that many common containers, such as WD-40 spray cans etc (maybe even a disposable propane bottle*) could be used for the coupling.
* if you use the propane bottle, assuming it's the correct size, be very careful cutting it open! I could see bad things happening if not done with care!