Product review (5 stars): I'm glad I read the previous reviews
I'm glad I read the previous reviews.  Many of them mentioned the black O-ring being smaller in diameter than the original.  So I took the advice and swapped it with the O-ring from the original pump.  And everything worked great.  If I had used the O-ring that came with it, and it leaked, like a lot of people said, I would have returned it.  And wasted more time, more time without the washer.  So, the reviews are very helpful, in that regard.  The device was easy to install and has been working great since.