How do I identify the type of poppet I need for a corny keg?

#2 from CHI are not an exact fit and they don't work as good as the original ones. Anyone know where we can find the original ones with the black rubber top vs the yellow? The yellow ones work, but not nearly as well as the originals. I find they stick and leak unless poked.

I did need to take the posts out to figure this out. Took a while to get my hands on the right wrench. Needed a 7/8" 12-point wrench, which was not available outside of an expensive set and the local hardware store or home depot. Ultimately ordered this one on Amazon for under $6, which worked. They look like the standard Cornelius/General Beverage ones (#2 from CHI). Expensive! Wonder if those cheaper universal ones work as well. Also looks like I'm going to need to replace the relief valves at some point, these ones are pretty grody.

This may not work for every keg, but I've had great success with "universal fit" poppets on my Cornelius and Firestone kegs. They take the guessing game out of finding an OEM part by picture on a website or catalog. Here's an example, this is one that I've used. http://www.ontariobeerkegs.com/product_p/unipoppet.htm

I imagine the safest bet is to unscrew one of the posts and get the same kind of poppet as the one you've already got.

It's hard to tell just looking at the top of the keg, so don't take this as certainty, but those keg posts look like firestone posts. I have pepsi kegs, with firestone posts, and use poppet nr. 1 from CHI.

You can also narrow it down by elimination. On the CHI page for #2, it says that #1 is a cheaper alternative, so we rule that out. I'm guessing you don't have a plastic insert, which rules out #3 and #4. You'll see immediately from looking at the poppet in your own kegs if it has long legs. I'm guessing not, ruling out #5 and #6.