I needed a replacement pressure gasket for my BES840 XL. I purchased three different gaskets, as the text only said BES840, without the XL designation, and for each one there were several "doesn't fit" or "leaks" comments in the reviews. By visual and tactile comparison with the original, this gasket was identical. I installed it (easy, except the metal screen needed to be tightened until it reached a hard stop), and it held pressure and did not leak a drop on the first pull. Twisting in the group head was quite tight the first time, so I used the tiniest bit of coconut oil on the rim of the grounds cup the first time I twisted it in.
It should be noted that the other two gaskets, which seemed slightly smaller in diameter, and had more rounded outer rims, MIGHT have fit well, also. I did not try them as this one worked fine for me.
