Delivery Confirmation - Send your products with Delivery Confirmation and track packages with 1 click. Pony Express is the on (USPS) United States Post Office product built from the ground up for the MAC. Save Time. No need to stand in line at the Post Office, fill out your Delivery Confirmation forms. Batch Mailings. If you are a large volume mailer and need a solution that can stay up with your demands, Pony Express offers a import feature for print large mailing lists. Version 1.3 have removed the 2 label limit on our product.