Yes. That is exactly what a #9 Remittance Envelope is. A #9 is considered a "reply envelope" and is often found inside the outer mailed #10 envelope. When looking for extra space with a long flap, the #9 Remittance Envelope is exactly what you need. #9 Remittance: 7 3/4" x 8 7/8" when flat, 3 7/8" x 8 7/8", or 3.875" x 8.875" when closed - A Donation envelope with expanded areas to print on the oversized flap which is 3.625" tall.