JAM Paper #10 business envelopes have wide straight flaps with dependable gum closures to keep items secure in transport. These envelopes are made out of 28lb, high quality paper. This pack contains an even total of 50 envelopes for any home or office mailing need! The size of these envelopes makes them perfect for three-time-folded standard sized sheets of paper. Use these envelopes for letters, documents, forms and more. Details:Available in multiple colors4.125" x 9.5" (#10)28 lb. paper50 envelopes