Large 9 x 12 Business Envelopes Our large 9 x 12 envelopes are custom printed with your business name and address. These envelopes are used to mail large catalogs, brochures or any material that does not fit in a small size envelope. Printed on durable 24# Kraft paper and custom printed with your name and the wording of first class on the edges. These large business envelopes are open end 9 x 12 with an imprint area of 8 x 10.75 inches. Print it 4 Less is your best source for Large Business Envelope needs needs.