Plastic Coated UrAmask - Blue is a Urethane Grade, 100% holdout material.  It is constructed of ground newsprint paper with the plastic overlay creating the strength of the material.  The blue coloring is used because of psychological studies showing men prefer this color.   APC has chosen a slightly lighter, cleaner blue dye than most of the competitive suppliers.  Premium Quality Paint Shops use this higher grade masking material because it eliminates paint bleed through, thus cutting down on the detail clean-up work necessary with lesser quality materials.