rent a PO Box, two different forms of identification are required. At least one of them must be a valid photo ID. This also applies to others who wish to share the box with the original subscriber's permission, and are of legal age. The post office will not forward mail from a PO Box until the box is closed, and then only to one address for all subscribers. As part of the agreement to rent a PO Box, if the PO Box is used for business, the Post Office will provide, upon request, the geographical (street) address of the business. Street Addressing Until 2012, only items mailed or shipped via USPS could be received at a USPS PO Box. However, a service called Street Addressing has begun to change this. Once a permission form is completed by the box holder, Street Addressing allows private shippers, such as United Parcel Service (UPS) or FedEx, to ship items to a modification of the actual street address of the Post Office where the PO Box is located. The Post Office accepts the item, and places it in the PO Box or, for larger items, handles them the same way they would a package sent via USPS. (Some have storage lockers.) Only certain Post Offices offer Street Addressing, and even for ones that do, it may not be available to all of its PO Box customers (e.g., boxes without a fee). Other restrictions also exist, including the same limitations on items that cannot otherwise be mailed by ground service though USPS. (Not to be confused with items that cannot be shipped by air.) In many cases, the package may require one additional business day for delivery, and the service was never intended for overnight delivery. Also, federal holidays not observed by the private shipper might cause a delay. If an item is shipped using Street Addressing in which the box holder did not properly sign up for, it will be returned to sender. Street Addressing will have the same street address of the post office, plus a "unit number" that matches the P.O. Box number. As an example, in El Centro, California, the post office is located at 1598 Main Street. Therefore, for P.O. Box 9975 (fictitious), the Street Addressing would be: 1598 Main Street Unit 9975, El Centro, CA. Nationally, the first five digits of the ZIP Code may or may not be