They are excellent protection for documents, negatives, art work and books. The tyvek envelopes can also be printed on, they are well suited to offset, lithography, letterpress, screen process, ink jet process. These envelopes will last up to 30 years if not exposed to ultra violet light, with their superior strength, flexible, will not rip or tear. The tyvek is 10 times stronger than paper, will not crease, crack or split. They resist water, chemicals, rot and mildew. Will not discolour and are lint free.