Selecting a Mailer on Amazon.com

Mailers, also known as shipping mailers or shipping envelopes, are designed to package and protect small items for mailing. The mailer may include padding or have a rigid construction to protect its contents. Bubble mailers, or padded envelopes, typically have a paper or plastic exterior and an air-filled bubble lining that is light weight yet protective and resistant to sudden impact. Some padded mailers may be lined with recycled newsprint or foam for cushioning instead of bubble lining. Rigid mailers, also known as stay-flat mailers, are made from a strong, rigid cardboard or plastic that is suitable for shipping items that are vulnerable to bending, such as documents and photos. These may also include a padded liner.

Many mailers have an internal flap with a pressure-sensitive, self-sealing adhesive or a gummed adhesive for closure without the need for tape; however, some types may require tape. A mailer that has a paper exterior is durable and lightweight. A plastic mailer, also called a poly mailer when made from polypropylene, provides resistance against water and tearing and may be rigid or flexible depending on the type of plastic and shape of mailer.

An envelope mailer is available in several sizes that correspond to specific widths and heights, the most common being 00, 0, 2, 4, 5, and 7. Envelope mailers without a padded lining may be defined only by width and height. Measurements typically include the flap extended.