What are the different classes of mail?
First Class mail cannot be opened by a postal inspector. Mail such as invoices for services received must be mailed first class. Second class mail is for subscriptions such as magazines. Third class bulk mail no longer exists…it is called standard class mail. It is not sealed to postal inspection. Mail weighing less than 16 ounces and not mandated to be mailed as first class can use standard class mail. Postage savings can be significant over first class mail.
