Metric and Marelon and Valves, oh my
Mine is 1.25 inches, but if yours says 25mm on it, I would call Forespar. Mine was marked in inches when I took it off, not marked in millimeters.
History trivia... All of these composite valves and fittings were originally from RC Marine in Australia. Company was bought by Forespar in the late 80's or early 90's.
After that they continued on with the the original tooling like the original ones in your boat, but by the early 90's developed a new design which is still in production. I am not sure about the sizing ID.
When I removed all of the original EY-installed valves screwed onto thru hulls, I replaced with the then-new series 93 (aka "OEM valves"). All of ours are, since then, true sea cocks. That means that the valve body is directly bolted to the backing place or clamped on by the outer threaded piece.
I recall that our original ones were stamped with the Australian label.
In our case, the new inner valve body and outer piece were screwed together with epoxy mush on both sides and after curing the outer flange was ground off.
Perhaps this makes our boat .003 nano knots faster. Perhaps.
One thing that (AFAIK) has not changed yet is the slight hydroscopic nature of the ball material. i.e. it expands slightly with water. This is the reason it gets more difficult to turn as the years go by. Forespar sells a proprietary lubricant for this, but we have not tried it.
This one drawback is inconvenient, but to me the alternative of electrolysis rapidly destroying a bronze thru hull is just as bad or worse.
"Everything's a compromise" .... everywhere in life.