Japanese Hinomaru with a thin white border, ideal for all manner of Japanese kit. The Hinomaru was usually given a white border when placed on dark surfaces, such as green or camouflaged aircraft. This is also the design used by the Japanese air force after WWII, right through to the present day.
These decals are scaled to represent 30", 36" and 48" roundels in 1/300 scale. (They're also ideal for large aircraft in 1/600; equivalent to 60", 72" and 96" diameter.) The actual diameters are 2.5mm, 3mm and 4mm.
These designs are of course supplied on the same paper as all of the others (actually a very pale blue) I've just given them a coloured background so that the white border is visible.