USPS Bulk Mailing Regulations

USPS Bulk Mailing Regulations


Effective January 22nd, 2023, the USPS now requires the use of flat trays instead of sacks to submit Marketing Mail and Periodical Class mailers. These flat trays must also be strapped to ensure mail is more secure during processing and transportation. There is a temporary grace period for the new flat tray requirements, through February 21st, 2023. This time will allow mailers to modify their operations and adjust their mailing plans. Here is what you need to know to ensure you are properly packaging your bulk mailings by then.

Flat Tray Mailing

  • The minimum number of pieces for each pricing level has changed for nonbarcoded flats of Marketing Mail. Minimums have not changed for barcoded flats or Periodical Class flats.

  • Flat trays must turn the tray lids inside out so that the white side shows instead of the green.

  • Each covered flat tray needs to be secured with two plastic straps placed tightly around the width of the tray (shorter side). The USPS does not provide the strapping material. 

Strapping Requirements

  • The USPS states that strapping must have a minimum tensile strength of 70 pounds, with elongation before yield of less than 20 percent, and 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.

Strapping Options

From low to high volume, Rocket Industrial has a variety of strapping options available to fit your needs for bulk mailing.

Postal Approved Poly Strapping Kit

Postal Approved Poly Strapping Kit

This postal approved poly strapping kit contains everything needed for low-volume strapping applications. Loop the poly strapping through buckles, then tighten and cut with the tensioner/cutting tool. This kit includes:

  • 1/2" x 9000' plastic strapping

  • 1,000 plastic buckles

  • Tensioner/cutting tool

RI-200 Battery Powered Strapping Tool

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 S600 Arch Strapping Machine

Eagle S600 Arch Strapping Machine

The Eagle S600 arch strapping machine is good for high-volume strapping applications. This arch strapping machine has a quick and easy loading process. 

  • 3/8" or 1/2" strap size

  • Uses polypropylene strapping

  • Up to 37 straps per minute

*Please check with your local USPS office to ensure proper mailing procedures. 

Not sure where to get started? We can help. 

Our packaging specialists are ready to help ensure you have the proper materials, tools, and machines for bulk mailing. Contact us for assistance in choosing the best option for your application.