Different types of specialty envelopes include coin envelopes, key envelopes, compact disc sleeves, credit card sleeves and document envelopes. Other types include mailing envelopes, which may feature sections to include shipping labels or designations on special shipping instructions as well as privacy envelopes and lined invitation envelopes.
Coin envelopes are significantly smaller than standard letter envelopes. They typically appear in a portrait orientation and feature a sturdy paper construction to allow the storage of heavy coins without tearing. Key envelopes share a similar design, in that they are small and sturdy to support the weight of their contents, with some also offering a winding mechanism to seal, rather than adhesive, allowing for repeated use. Compact disc sleeves are a type of envelope that includes a clear plastic section on one side to allow visibility for the label of the disc. Credit card envelopes are the size of a standard credit card, but they often feature an open end with no seal and a cured edge to allow users to insert and withdraw the cards.
Many private and public mailing services offer a variety of specialty envelopes to handle different types of documents or shipping situations. For example, the U.S. Postal Service offers padded envelopes to protect the contents as well as Priority Mail envelopes that ship at an expedited rate. Many paper and office supply stores also sell envelopes with different colors and materials on the inside for use in mailing sensitive documents or special missives.