These 9 x 12 First Class Open End envelopes are printed with a green diamond border and the words “FIRST CLASS MAIL” . Printed diamond border is on front and back of the envelope. Use this to send flat, bulky materials or a number of smaller items, such as coins, catalogs and jumbo cards. These envelopes are available in a variety of sizes, have a center seam construction, and are also frequently referred to as “catalog” envelopes. The amount of flexibility provided by these multipurpose envelopes makes them a great addition to any environment that handles a variety of object types.