bmstrong,
I've bought 0-rings from sigman in the past and I can part with a glow-o-ring that is ~1" OD - would appear to be the same as what I have in my Ti-PD. Drop me you address by PM & I can have it to the mail to you on Monday.
In the mail (Tuesday am).
If anyone wants to send (sell) me something I'm looking for 2 or 3 of the low-force PD springs...., I previously bought 3 but now have too many McGizmo PD lights....
Neale