Merc superseded their 22-806608a02 to 22-8m0119211 It looks more durable now kinda similar to the Volvo one w/o tether though. That's a pic of the old one reference.
I replaced most all my blue ones with the Hardin marine stainless ones. Did find that getting them to screw into the plastic exhaust manifold elbows was a real issue. Decided to give up and put the plastic ones back in