Didn't need this part...read if you are having problems with the toilet running for no apparent reason
I ended up not using this flush valve as the running toilet was caused by something else (read on to find out what). 5-Star review based on valve price and shipping speed.
While I have installed and repaired countless toilets, this was my first top flush toilet and diagnosing the problem was giving me fits. The toilet would run intermittently. I knew it wasn't the fill valve, but it also didn't seem like the flush valve, which I had taken out inspected and cleaned. It turns out that one of the tubes (partial flush tube) from the push button to the flush valve had worked it's way down and was pushing the flush valve partially open. I'm sure folks had encountered this before, but my internet searches never found this problem. It was an easy fix to shorten the tube length by screwing it in more.
Also, I appreciated that not only did Swiss Madison not gouge me on the price of the flush valve, but it came really fast after ordering. I'll hold on to the flush valve in case it ever does fail.