The decals are specifically sized to fit Ghukek's Arleigh Burke class flight II STL prints at 1-1800 scale. They will probably fit other designer's stls. The set includes stern helo decks, bow VERTREP boxes, bridge radar panels, windows as well as multiple vent pannels.
 
They are printed on clear water slide decal paper.
 
They are made to fit on a "soon to be released" version that does not have the recessed markings.
Even so, they can still be used on already printed ships. Use a small brush to fill the recesses with liquid resin, cure and lightly sand level.