néo6, le couteau de poche au design soigné, facile à vivre et durable, pour tous et pour tous les jours
www.opinel.com
There is an animated diagram of the mechanism about half way down that page of the European Opinel web site. No back spring. It's cam action, with a hump on the tang of the blade acting against the ring. I don't mind the cam action instead of the locking ring, but that rounded tip is a no-go for me.
I imagine that Opinel knows its customer base well enough not to offer that illegitimate creation on their US web site. As others have noted, it was plainly developed for the EU market.