These are cut to the panel contours rather than supplied as a universal sheet, so they are matched by part number and by body style rather than by dimension.
Decals fail from UV and from pressure washing at close range: the edge lifts first and then water gets under the film. The same graphic is often offered in two or three colourways, and each colourway is a separate part number. Fitting needs a clean, wax-free surface, an ambient temperature above about 15 °C and a squeegee — trapped air is what makes a decal look amateur a month later.