Because FedEx's SmartPost service works with the United States Postal Service, it can deliver a package to any residential address in the country or its territories -- including post office boxes and military addresses. FedEx SmartPost emphasizes low-weight shipping, with a maximum of 70 pounds and 130 inches in girth and length. Because the USPS boasts Saturday delivery at no extra cost, the same holds true for FedEx SmartPost.

How FedEx SmartPost Works

You can bring your package to a FedEx office for shipping, or arrange for the company to pick it up at your business or home. Your package is scanned through FedEx's state-of-the-art system, and you can track its progress online. FedEx ships your package to the recipient's local post office, and the USPS performs the actual delivery of your package to the destination. Delivery takes between two and seven business days, depending on the destination zip code. All packages include a prepaid USPS shipping label, if returns are necessary. The USPS will pick up the return for free from the delivery address, or you can bring the package to a USPS or FedEx office.