Number 11 regular envelopes are slightly larger than the standard business #10 envelope. If you want to use the number 10 as return/reply you will want this envelope. A number 10 will fit inside a number 11. It has more room then the number 10 allowing for additional folded pages. It is small enough to qualify as a letter so it will not cost extra for postage based on size. Other common uses for the number 11 include using them for patient records and media kits.
Number 11 Regular, Color: White, Size 4.5”x10.375”, Weight: 24#