The ultimate in durability and strength, Tyvek catalog envelopes are the ideal choice for sending mails to long-distance domestic and international destinations. Instead of using paper, these envelopes are crafted out of Olefin. This material grants these envelopes incredible strength and water resistant properties. This 12 x 15.5 - 14 Tyvek open end catalog envelopes have a bright white color. Offering a convenient sealing mechanism, these envelopes come with branded Kwik-Tak seal. The Kwik-Tak is a type of pressure-sensitive sealing system that requires no moisture. This envelope has no windows and a sturdy mid-seam construction. These envelopes have a formal look and a smooth finish.