These booklet envelopes are made out of smooth 24lb paper. They're ideal for enclosing standard sized sheets of paper without bending or folding. Each one has a straight flap with a reliable gum closure to keep enclosed items secure in the mail. Use these envelopes to mail forms, files, documents, manuals, and more!Details: Available in multiple colors9" x 12"Made from 24 lb. paper25 envelopesFeatures straight flap