Special flap profile envelopes designed to run on all known mailing machines. Board inserts in the box ensure product remains flat for optimum runnability. All products feature gummed sealing and 'side seams inside' style of manufacture. Window: 39x93mm, 22mm in, 18mm up. White, opaque. 90g/m². Size: DL 114x235mm. Boxed 500.