I took Red Eye o-rings to work and measured them on the Parker o-ring measuring fixture. What I received were US-sized o-rings that were close to, but not exactly the metrics Honda specifies.
I contacted Red Eye and asked about what he sent. He responded (sternly) that he knew more about o-rings than Honda. I used his o-rings on the intake tubes and they worked. Some owners have reported needing a lot of force to install those red o-rings for the back wheel. Probably not the exact Honda specified size.
Now, Red Eye never stated that his offerings were metric. But, for the rear wheel, I'll continue to use metrics.
I purchased his o rings in January of this year for the rear wheel service, had no issues using them. If you purchase something from the site that shows in stock he will ship it and send you and email. He does not however answer every random question sent to him.