The hull numbers are thermally printed on clear waterslide decal paper. They are white with black shadow.  They are sized to fit GHQ models but will mostlikely fit other manufactures as well as Shapeways 1-2400 scale prints.  There are 3x (incase you have a tragic actident during application) of each hull number 40-43, 46-58, 60, 62-67, 80-84 and 86.
 
The decal picture is with a GHQ Oakland Light Cruiser (w/o turrets) hull for scale purposes.