5 1/2 x 7 1/2 Booklet Envelopes JAM Paper is the ideal brand to supply every item you need to make sure your business runs smoothly. These standard white envelopes are perfect for getting the job done, sending your messages in a professional style. Our envelopes come in a wide variety of colors and fashions, but if you're looking for a basic solution with a formal look, the white commercial envelope with a horizontal flap is the perfect choice. The 5 1/2 in x 7 1/2 in envelopes are suitable for business invitations and specially-sized documents.