Publication 248 - The Perfect Bundle
November 2006
PSN 7610-08-000-1439


The Perfect Bundle

What is a bundle?

A bundle is a group of addressed mail pieces that a mailer assembles and secures together before mailing. The individual pieces in a bundle are presorted for delivery to a special area. Bundles of flat-size mail pieces are secured with banding, shrink-wrap, or a combination of the two. Banding may include clear plastic bands, rubber bands (for lighter bundles), or string that maintains enough tension to keep the bundle intact during processing. Wire or metal banding is not permitted. The address block on the bundle — containing all address information, including the optional endorsement line and any barcoded, pressure-sensitive, bundle label — must be visible and readable to the naked eye. If shrink-wrap is used, it must be transparent and seams or imperfections such as heat creases should not appear over the address block. If banding is used, it cannot obstruct any part of the address block. Tight, clear, smooth banding will never obstruct the address block.

Why the "Perfect Bundle"?

That's easy. It helps your bundled mail get as close to the delivery point as possible — as quickly as possible and in the same good condition as when accepted. Perfect bundles help us to control costs and provide you with the most efficient service possible.

Examples of improper shink-wrap and banding.

Shrink-wrap creases and opaque banding can make the address unreadable and delay delivery.

Why are bundle integrity and address visibility important?

We want to make sure you get your money's worth when you mail with the Postal Service. Bundles are subject to handling and jostling while they are being transported and processed. You protect the mail — and your investment in your customers — by helping to prepare the perfect bundle. Bundles that are securely prepared are less likely to break open during processing. When they do break open, the value of your presort work is lost, adding to delivery time and increasing the chances of damage to individual pieces. And if all address information isn't visible and readable, that can also result in processing delays. In either case, the result is less efficient handling of your mail and increased costs. As we deploy state-of-the-art automated package and bundle sorting equipment throughout the Postal Service network, it's more important than ever that your bundles can be processed using this efficient technology.

Example of torn shrink-wrap and loose bundling.

Torn shrink-wrap and loose banding can damage your mail

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What else should I know about the Perfect Bundle?

• Bundles must be double-banded, shrink-wrapped, or both.

• Thinner bundles have a tendency to curl, making it possible for individual pieces to slip out. Double banding, if tension in the bands is maintained, or shrink-wrap can be effective solutions.

• Bundles that are more than 1 inch thick must be double banded or shrink-wrapped. If banded, at least one band must encircle the bundle's length and another must encircle its width (girth). More bands are permitted, provided that none are within 1 inch of the bundle's edges. But opaque banding may not cover any element of the address block.

• Banding must be tight enough to keep individual pieces from slipping out. A band is tight when it depresses the edge of the bundle. Loose banding is not permitted.

• If twine or string is used for banding, the knots must be tight enough to stay secure during processing. Slick twine or string that won't form or hold a tight band or knot should not be used.

• Shrink-wrap of insufficient strength or with large openings that tend to let pieces slip out is not acceptable.

• Do not secure large, heavy bundles with rubber bands, thin shrink-wrap, or banding, which does not maintain sufficient tension when stretched in normal handling.

What if I prepare my bundles in sacks?

Bundles placed in mail sacks experience much more movement than bundles placed in firm-sided containers or on pallets, increasing the chances that they may come apart. And bundles containing pieces with covers of coated stock — which are more slippery — can contribute to instability during handling. That's why some special steps — in addition to those listed here — must be taken to protect bundles prepared in sacks.

• If the pieces in a bundle have covers printed on coated stock and they are not individually enclosed in a mailing wrapper, the bundle cannot be more than 3 inches in height (thickness) unless it is secured tightly with double plastic bands or with shrink-wrap plus one or two plastic bands.

• If the pieces in a bundle have uncoated covers or outer surfaces, the bundle cannot exceed 8 inches in height, although a maximum height of no more than 6 inches is recommended.

• A bundle that exceeds the maximum height by less than the thickness of a single piece in the bundle meets the height standard.

What about bundles containing uneven pieces?

Counter-stacked bundle Counter-stacking individual pieces can help create a more uniform and stable bundle. This makes them less likely to come apart. Counter-stacking, with groups of pieces facing in alternating directions, should only be used to create a more even bundle.

Counter-stacking is most appropriate for saddle-stitched pieces and pieces with one edge or corner thicker than the others.

When counter-stacking, all addresses should face up and the individual pieces should be divided into no more than four equal groups, but with as few groups as possible to create a bundle of uniform thickness. For example, a tall bundle of uneven pieces should be divided into four groups of approximate equal thickness. The first and third groups would be address side up with the bound edge to the left. The second and fourth groups would be address side up with the bound edge to the right.

But counter-stacking isn't the best solution if the individual pieces are thicker in the center than along the edges or corners. If that's the case, the height (thickness) of the bundle should be limited to 3 to 6 inches and the bundle should be securely bound with banding, shrink-wrap, or both. This will help keep the bundle stable and in one piece. Shrink-wrap of insufficient strength or with a large opening in the shrink-wrap that tends to let pieces escape is not acceptable.

How can I be sure my bundles are prepared securely?

We recommend an easy test to simulate the stress of normal transit and handling. Prepare a few bundles following the simple guidelines in this brochure. Then place the bundles on a surface about 4 feet above the floor. Push each one off with enough force for it to land on a corner at a distance of 1 to 3 feet from the starting point. Then lift each bundle by grasping a corner, either the shrink-wrap or a few pieces. If the packaging doesn't detach from the rest of the bundle and no pieces come out while lifting, it's likely to withstand normal transit and handling.

Remember, in order to create the perfect bundle it is important that you follow the applicable Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM®) and use materials that are appropriate for the types of mailings you prepare. You also need to properly maintain any equipment used to apply these materials and periodically test your bundles to ensure they will maintain integrity through the Postal Service network.


Help us provide the sevice you expect — perfect your bundles.

Want to know more?

It's important to us that you have the information you need to help create the perfect bundle. This brochure is a good place to start. But if you have questions or need more information, the following resources may be helpful:

• Link to the DMM on Postal Explorer at and search on "bundles."

• You can also contact your local Business Mail Entry Unit.