Check delivery time estimates on the Priority Mail Delivery Map. There are specific regulations and standards for mailing restricted, prohibited, and hazardous materials, including cigarettes and smokeless tobacco. We help businesses provide these services and resources to their customers at discounted rates. With more than one size to choose from, the boxes combine the speed and convenience of Flat Rate shipping with regional, distance-based pricing to reduce costs. Please note Regional Rate Box C was discontinued. Regional Rate Boxes A and B are best used for small, dense packages being sent short distances. In most cases, the expected delivery date printed on your receipt or provided at checkout will reflect a delivery time of 1, 2, or 3 business days and is based on origin, destination, and drop-off time. The expected delivery data does not come with a money-back guarantee. For mailable items up to 70 lbs. For details on free Package Pickup, visit Schedule a Pickup.