JAM PAPER #11 Business Commercial Envelopes - 4 1/2 x 10 3/8 - White - 25/Pack White Commercial / Business Envelopes Size: #11 (4.5 x 10.38 inches) Quantity: 25 Envelopes per Pack This Envelope is fashioned from High Quality 28 lb paper, has a gummed commercial flap, and a smooth finish. Perfect for personal mail, business mailings, greeting cards, announcements, and so much more!