Strong adhesive force through two heat-sealed neodym strong magnets. Blue plastic back and transparent window made of heavy-duty polypropylene. Suitable for scanners and tear-resistant. Suitable for external use because rain protection flap protects documents against dust and moisture. Use on metallic surfaces. Such as meshed containers. Pipes and moveable transport containers. Inserts can be exchanged quickly. Internal dimensions: a4 landscape external dimensions: 311 x 280 mm w x h pack of 10 pieces.