10W laser O-Ring - Missing?

Upgraded my E2 to 10 Watts last week. It’s been performing well and doing its stuff in almost half the time!
But after several hours of use, I thought the performance was going off a bit, so I watched Gil’s video on cleaning the 10-Watt laser unit. Cleaning the Emblaser 10-watt laser unit - YouTube
In his vid at 4:14, he shows the inside of the brass lens cover with the quartz glass and a rubber O-ring inside. - But I don’t have that O-ring!
I cleaned the glass (nothing visible came off on the tissue by the way), screwed the lens cover back up tight, and carried on cutting. But I’m wondering if there should be a sealing O-ring in the lens cover.
Have other users of the 10Watt upgrade kit got the O-ring fitted shown in Gil’s video? Or is mine missing?

Hi Mike,

We used an o-ring on the first release of the 10w units but ultimately found it wasn’t necessary.

Your unit is fine without the o-ring.


Hi Dominic,
Thanks for clearing that question up.