TotalBoat Topside Primer is a very unique marine primer, in that it works great with one-part paints, but it is also compatible with two-part urethane paints. Most other one-part primers do not have this ability, and do not have the resistance to the solvents used in two-part urethanes.
As with any product that you are less familiar with, we always recommend testing first in a small, inconspicuous spot to check for adhesion, application properties, and finish.