USPS Bulk Mailing Regulations

The United States Postal Service (USPS) now requires all Marketing Mail and Periodical Class flats to be submitted in flat trays, rather than in sacks. These trays must be securely strapped to improve handling and reduce mail damage during processing and transportation. Whether you’re mailing magazines, catalogs, or marketing pieces, understanding the latest USPS bulk mailing requirements is critical for compliance and avoiding rejected mail.

As of July 2025, the USPS has announced several updates to flat tray and bundling requirements. These changes aim to improve mail security and streamline processing.

To meet current USPS standards:

• All bundles of flats (except exceptional dispatch newspapers) must be secured with two or more cross-strapped bands or shrink-wrapped plus strapping.
• Rubber bands, twine, or string are no longer allowed for securing bundles, except for First-Class Mail flats in flat tubs.
• Mailings of 500 flat-sized pieces or fewer may be placed loose in flat trays without bundling.
• Bundling at 5-digit, 3-digit, and ADC presort levels becomes optional for First-Class Mail and USPS Marketing Mail flats, encouraging the use of full flat trays instead of bundles.
• A full flat tray must contain at least 125 pieces or weigh 15 pounds, whichever threshold is met first.
• Tray lids must be turned inside out so the white side is visible instead of the green.
• *Please check with your local USPS office to ensure proper mailing procedures. 

• The USPS states that strapping must have a minimum tensile strength of 70 pounds, with elongation before yield of less than 20 percent, and a minimum tension of 10 pounds. Any color strapping is acceptable as long as it does not interfere with the visibility of the label.
• Sealing of strapping can be achieved by welding the ends together using heat or friction, using a non-corrosive plastic buckle or seal, tying a knot, or using self-locking straps.

Rocket Industrial offers postal-approved banding, strapping tools, and machines to fit any mailing volume.

RI-200 Battery Powered Strapping Tool

The Rocket Industrial RI-200 battery powered strapping tool is a good option for medium-volume strapping applications. This tool is lightweight and designed to be used with one hand, weighing only 8 pounds.

• Includes 2 batteries & charger
• Adjustable strapping tension from 90 - 450 lbs.
• Accepts 1/2" - 5/8" width strapping

Eagle 710 Arch Strapping Machine

The Eagle 710 arch strapping machine is good for high-volume strapping applications. This arch strapping machine has a quick and easy loading process. 

• 5mm, 6mm, 9mm, or 12mm strapping
• Uses polypropylene strapping
• Up to 65 straps per minute

Staying up to date with USPS bulk mailing regulations is essential for avoiding costly delays, rejected mail, or compliance penalties. Whether you need a battery powered strapping tool for small runs or an arch strapping machine for high-volume operations, the right equipment ensures your bulk mailings are secure, compliant, and ready to move through the postal system.

For a look at how evolving regulations affect packaging across industries, explore our blog on packaging compliance to stay informed and prepared.

Our packaging specialists can help you choose the right strapping tools, machines, and materials to meet USPS requirements. Contact us for assistance in choosing the best option for your application.