Ensure your postage arrives to its destination intact with first class catalog envelopes! This item fully encases your letters in a lightweight, moisture and rip resistant envelope. It provides a clean, crisp look that conveys a professional appearance for a wide range of applications. We offer options with a self-adhesive flap eliminates the need for licking and seals your mail securely so it is ready to fly first class. However, a regular moistening seal can do the trick as well.