Heater Pipe o-ring size? (e301-15-287)
 

Ok, I can find the part number, but I really just want to order a pack of the right size but cannot find it anywhere (and don't have any good ones to measure on hand). Has anyone actually measured what size they are?

I am assuming they are some oddball metric thing.

Worst case I will pay the $7 to have an OEM one show up and then just measure it.