Cumberland C4 Self-Sealing Envelopes – 90gsm White | Box of 250

You've tried to stuff a folded A3 or a thick legal doc into an envelope and watched the seal split before you even posted it. These Cumberland C4 envelopes are built for that job. 90gsm stock sits noticeably thicker than standard 75gsm, so heavier inserts don't burst the seam. The self-sealing strip means one firm press and it's locked — no glue smear, no tape hunt. Clean white finish keeps your mail-out looking sharp. Box of 250 gives you a proper run of larger-format documents without reordering mid-week. Add to cart

• C4 size handles folded A3, legal documents, or brochures without crumpling
• 90gsm stock — thicker than standard 75gsm, resists tearing at the seam
• Self-sealing strip: one firm press, no glue or tape required
• Clean white finish for professional mail-outs and document dispatch
• Box of 250 — a solid run of larger-format correspondence