AR Lens too thin. What to do?

I finally received my parcel from intl-outdoor… SG post is reeeeeeeeeally slow.
and in the parcel some gorgeous AR coated lens for my C8.
Unfortunately when i placed one in a KD C8, it keep rattling.
Compared to the KDC8 lens, looks like it is 0.5mm too thin. :~
So what can I do to stop the rattling?

Thicker o-ring?

The rattling is one of the effects, but worse yet, out of focus, loss of lumens/throw, possible damage to the LED, etc.

If a thicker o-ring doesn't work out, not familiar with the KD version of the C8, but like most lights, all these dimensions are critical to getting everything fitted properly. To make up the gap, could try to find a slightly larger reflector (in height), or raise the star by either adding a copper, brass, or aluminum disc/round under the star or loosen the pill. Loosening the pill may cause intermittent connectivity, but just may work fine as well. You could rig up some sort of shim for the pill to tighten up to, but raising it's position.

Stack two normal o-rings in the bezel and don’t screw it completely.

If it happens to mine, I would apply a layer of glow-in-the-dark paint in the bezel where it contacts the lens. I would trade glowiness for waterproofness.

Check cnqualitygoods they have a lens which seems a bit thicker.

I usually stack o-rings or find a thicker o-ring to take up the slack.

thanks guys, i’ve tried a glow-in-the-dark O-rings from another C8 between reflector and lens and it’s perfect.
Now I need to order that same O-ring else one of my C8 will be missing an O-ring.
Anyone knows a vendor that sell spare O-rings that won’t take an eternal 8 weeks to deliver orders?

How is it assembled that the lens thickness affects how the reflector sits on the LED/star?? No insulator?