checksimple personalized #10 self-seal standard mailing envelopes - (500 envelopes) custom non-window checksimple these customizable pre-printed #10 standard mailing envelopes save you time with a self-sealing flap and help convey your professional image. <br><br> <b>free return address personalization</b> on this envelope to include your business name and address. <br><br> <ul><li><b>multi-purpose:</b> use for mailing checks, invoices, statements and other communication. <br><li><b>self-sealing:</b> material on either side of flap adheres to itself to secure contents. <br><li><b>#10 non-window envelope:</b> a basic business necessity for mailing common document sizes like 8-1/2 x 11 letterhead!</ul>