9x12 Envelopes (Bright White) - Open Side 9x12 Booklet Envelopes - Pack of 55 White Envelopes 9x12 28lb Paper - Check O Matic DURABLE 28LB PAPER: These 9 X 12 white envelopes are made from 28lb heavy-duty paper. Its durable construction allows the booklet envelope to carry much thicker stacks of documents than ordinary 24 lb paper envelopes. TRUSTED GUMMED CLOSURE: This Check O Matic booklet envelope comes with moisture sensitive gum-lined flaps. This a trusted and convenient sealing technology that keeps the envelopes precious cargo secure. BLANK DESIGN: Perfect for formal correspondence, these 9x12 white envelopes have a completely blank design. This makes writing and printing on them extremely easy. OPEN-SIDE DESIGN: The open side booklet-style design of these envelopes makes inserting large documents much easier. These 9X12 envelopes are great for sending large brochures, reports, legal paper, large invitations, or any documents that cannot be folded. PACK OF 55: This pack of 55 booklet envelopes is great for both personal and business users. If you need to send out large unfolded documents every now and then then this pack is a great choice for you.