In fact, I don't know!
I use an
acrylic antifouling
paint made by the same company and
sold under the name "Neptal SE" in a chain of chandleries. I am satisfied with it: there are no more mussels and
barnacles on the
hull, only some weeds.
But I don't know if "Neptal SE" is the same as "Allegro Extra".
Alain