Definition:
Matter formerly classified as fourth-class mail is referred to as Media Mail or Library Mail.
Used For:
Packages weighing 1 pound or more.
Packages mailed within the continental United States may weigh up to 70 pounds and measure up to 108 inches in length and girth combined.
Note:
If you enclose or attach First Class Mail, First Class postage must usually be paid for the enclosure or attachment. (Ask us about incidental First-Class attachments or enclosures that do not require separate payment of First-Class postage.) You can purchase insurance to cover the value of articles mailed at the Standard Mail B rate. We also have information about lower local mailing rates andspecial mailing rates for books, catalogs, and international mailings.
Delivery Speed:
The delivery goal for parcel post is 2-9 days, depending on distance. For faster delivery of parcels, use Priority Mail or Express Mail.