Every year supplements for Denmark are published, the sheets for these are made of extra heavy paper (170 grs.) and fitted with plasticizer-free clamping strips.
Here you can store the stamps etc. issued in the previous year.
All sheets have frames where you can place the stamps, usually with a picture of the stamp itself. On all these frames are transparent clamping strips to secure your stamps.
Supplements Denmark are available vzn different years and often in multiple designs.