Svalbard and Jan Mayen are territories of Norway, and they do not have a unique official flag. Instead, they use the Norwegian flag, which has the following properties:

1. Colors: Red (#C8102E), white (#FFFFFF), and blue (#003896).
2. Aspect ratio: 22:16 (or 11:8).
3. Geometric properties: The flag consists of a red field with a blue Scandinavian cross outlined in white. The vertical part of the cross is shifted towards the hoist side.
4. Measurements: The width of the white and blue stripes on the cross are 1/6 and 1/12 of the flag's height, respectively. The distance from the hoist to the cross is 1/6 of the flag's length.

As Svalbard and Jan Mayen are under Norwegian sovereignty, they use this flag for official purposes.