and weighing 3.5 ounces or less, and that are not eligible for the card price.There are separate prices for stamped letters, and for letters with postage affixed (other than regular stamps) or imprinted (permit imprint) by the mailer (Metered Mail price).

In addition, bills include a demand for payment; statements of account do not include a demand for payment.

The debt does not have to be due immediately but may become due at a later time or on demand.

The debt asserted need not be legally collectible or owed.

The minimum postage per addressed piece is that for a piece weighing 1 ounce.

See , weigh a sample group of at least 10 randomly selected pieces and divide the total sample weight by the number of pieces in the sample.

Express all single-piece weights in decimal pounds rounded off to four decimal places.Keys and identification devices (such as identification cards and uncovered identification tags) that weigh 13 ounces or less may be returned at the applicable single-piece First-Class Mail parcel price plus the fee.Keys and identification devices that weigh more than 13 ounces are subject to Priority Mail prices under .The key or identification device must bear, contain, or have securely attached the name and complete address of a person, organization, or concern, with instructions to return the key or identification device to that address and a statement guaranteeing payment of postage due on delivery. Pieces mailed at the card price are not subject to the nonmachinable surcharge.An envelope weighing no more than one ounce with one enclosed standard optical disc no larger than 12 centimeters in diameter that is mailed as letter-size BRM (see First-Class Mail (including Priority Mail) is the only class of mail eligible to receive the following extra services: Registered Mail service and Certified Mail service.See information regarding additional extra services in Bills and statements of account assert a debt in a definite amount owed by the addressee to the sender or a third party.