These envelopes are great for mailing letters, reports, catalogs, statement, certificates, photos, bills, checks, and more.SpecificationColor: BrownMaterial: PaperStyle: Double Sided WindowThickness: 1mm / 0.04 inchOverall Dimension: 10 x 8cm / 4 x 3 inch (L*W)Package Content: 10 x Window EnvelopesAdvantagesMade of sturdy and durable paper in fine workmanship, reliable, wear-resistant, and is not easy to break.Comes a unique transparent window design can fit for various mailing usage, and keep the contents in good condition.InstructionEasy to use: Insert the letters into envelope, then fold the closure and put the glue or sticker on it to increase the closure tightness.NoticePlease kindly note that this window envelope does not include glue.