Dutch neutrality triangles (used 1939-41) primarily intended for 1/300 scale aircraft.
These decals are scaled to represent 30", 36" and 48" sizes (side length) in 1/300 scale. 2.5mm, 3mm and 4mm side length. Please note that the black border seems relatively thicker on the smaller markings; this is correct, as the real thing was usually painted with a four inch black border regardless of the size of the insignia. This does mean that strictly speaking these aren't suitable for use on larger 1/600 aircraft such as Catalinas, but frankly they look fine....