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What Are Polybags?

The Polybag versus the Constructed Poly Envelope:
What they are, how they’re different and why it matters for direct mail.

Polybags for direct mailing

polybags and why they matter for direct mailing

We’re all familiar with the many types and sizes of polybags, thanks in part to eCommerce.  Polybags, also known as polyethylene bags, provide an economical shipping choice that protects against dirt, moisture, and tampering. Poly bags are used to ship, protect, hold and store just about everything from candy and food to clothing, books, nails, tools and automotive parts. Poly bags can be clear or opaque and can be printed with images and type. They’re available in several different thicknesses, referred to as mils, to protect and package as many different products as possible.  Lightweight polybags are cheap and used for temporary storage (think dry cleaning, newspaper, and grocery bags). Heavyweight poly bags are used when strength and durability are essential.

Although they may be called “direct mail specialty envelopes” in online searches, polybags aren’t designed for response-driven direct mail.

Why not? Should you care if you’re in the direct mail business?

Have you done all you can to ensure your mailer gets through postal processing, receives the lowest postage rate possible and makes it to the recipient?

If you’re not sure, this article will help by defining what polybags and EnvyPak clear constructed poly envelopes are; how they’re different; and why the constructed clear poly envelope is superior for direct response mail.

Specifically, this post will highlight a poly direct mail envelope that saves money on postage, sails through production and postal processing and gets superior results with its many creative possibilities.

A Modern Miracle

Before we outline the differences between a poly bag and a constructed poly envelope, let’s first take a look at what it takes for a piece of mail just to pass “go” and get through the postal system.

The U.S. Postal Service is the only delivery service that reaches every address in the nation – 155 million residences, businesses and post office boxes.

In one day, the U.S. Postal Service processes:

  • • 2 million mail pieces each hour
  • • 8 million mail pieces each day
  • • 212 billion pieces of mail each year
  • • 121,452 address changes

That’s an average of 324,638 per minute and 5,711 mail pieces each second.

And keep in mind, your piece will only be mailed successfully if you’ve designed your envelope for postal automation. For business mail, this refers to flat-sized mail that is 100% barcoded using an Intelligent Mail Barcode (IMb) encoded with the correct delivery point routing code that’s specially prepared for the postal service’s high-speed processing equipment.

Makes you think, doesn’t it?

Now, back to that question – have you done everything you can to make sure your mailer stands a fighting chance getting through the postage system?

Maybe you’re grappling with questions like these:

  • Will your mailing arrive quickly and to the right place?
  • Where should the label go? How should it be printed?
  • How should the mailer be sealed?
  • Can you print the address directly on the envelope, or do you need an address label?
  • What are mailer size restrictions?
  • Are your allowances for insertion tolerance correct?
  • Do you need a paper label for a barcode?
  • Am I spending more than I should on postage?

Constructed poly envelopes made specifically for direct mail

Working out the hundreds of precise details for a direct mail envelope that meets USPS requirements for automation isn’t something most people want to tackle.

Great news — It’s already been done. And the result is EnvyPak’s  Automation Letter Rate (ALR) envelope.

And nope, it’s not a polybag. EnvyPak’s Automation Letter Rate (ALR) envelope (or ALR)  is so much more.

ALR clear poly envelopes are designed for companies who want to get more from their direct mail efforts.  More results, more savings on postage and more “Wow!” in the mailbox.

The Automation Letter Rate (ALR) Envelope

The EnvyPak ALR envelope is a sturdily made, fully constructed four-sided clear poly envelope

with welded sides and bottom and a sealable flap.

EnvyPak clear poly direct mail envelopes are constructed with USPS approved crystal-clear 4.5 mil poly (not the flimsy 1.6 mil polyethylene used for polybags).

This clear poly envelope for direct mail provides creative flexibility, meets postal guidelines and sails through inserting and processing equipment with flying colors.

  • EnvyPak is also the only clear poly envelope that qualifies for automation letter postage.

There’s no way you could mistake these envelopes for poly bags.

USPS approval and poly envelope specifications

It took ten years of rigorous testing and engineering for this clear poly envelope to meet all USPS specifications for full automation rates.

Here are a few of the USPS specifications:

  • Height between 4” – 6”
  • Length between 8” – 10.5”
  • EnvyPak smooth anti-reflective polypropylene is required on address panel side
  • Address and IMB (International Mail Barcode) can be printed on insert to show through the anti-reflective polypropylene
  • Maximum clear gap of 0.2” (clear gap occurs when insert inside envelope shifts to the right inside of an envelope and it is possible to “see straight through” both sides of the envelope)

Click herefor the complete list of EnvyPak ALR envelope specifications.

EnvyPak Automation Letter Rate poly envelope vs the polybag

EnvyPak ALR (Automation Letter Rate) poly envelopes are designed specifically for direct-response mailing campaigns. Direct mail sent in an EnvyPak envelope creates a positive, emotional impact because you can see what’s inside. And you can also print directly onto the envelope.

There are so many creative possibilities with EnvyPak’s automated poly envelope.

You can print the address and barcode directly on the insert to show through the clear envelope, which allows for creative approaches between the insert and envelope design.

And finally, a paper address label can be eliminated with an EnvyPak envelope because the address can be printed on the inside content to show through.

Poly bags and the post office

The USPS will allow approved poly material to mail as a flat, which often doubles postage. But that’s not all. if you try and mail flimsy poly bags, you may be in for even more unexpected and unwelcome surprises.

Remember that cheap, thin 1.6 mil polyethylene most polybags are made from? It’s not automated for postage. Postal machines and scanners don’t like a thin, unevenly filled polybag. If the polybag has spaces where it’s completely flat and unfilled, the poly can fold, get caught in machinery and prevent the shipping labels from getting scanned properly.

A thin polybag that gets caught in machinery gets held up at the post office. And recipients are left wondering what happened and why it’s taking so long for their item to arrive.  You’re left holding “the poly bag,” so to speak.

Because they are constructed of rigid polypropylene, EnvyPak ALR envelopes will work exceptionally well throughout the postal process. It won’t fold over” and get caught in postage equipment.

Save on postage with full automation

And here’s the best reason to try an EnvyPak ALR clear poly direct mail envelope.

EnvyPak’s Automation Letter Rate (ALR) poly envelope can yield up
to 54.6% savings in postage, savings traditionally only attainable
with paper envelopes.

In fact, EnvyPak’s ALR envelope mails for the exact same postage as a paper envelope. Depending on the quantity you need, it can be manufactured for either hand or machine inserting the contents.

This opens doors for marketers, both large and small, to have access to a unique, high-impact clear envelope that drives response.

Still not convinced there’s a difference between a polybag and a constructed poly envelope?

Here’s what it boils down to.

If you could increase the odds that your direct mail piece would have an edge over all the competing items in a mailbox to attract the recipient’s attention and get opened – wouldn’t you do it?

Types of Clear Poly ALR Envelopes

The ALR envelope is available in three formats to suit your specific quantity, inserting and sealing needs. All three formats are USPS approved.

polybags for direct mail

Standard – for hand-inserting only. Printed side seams allow easy inserting and prevents a clear gap.

  • This is a 100% clear mailing envelope made from USPS-approved polypropylene
  • Offers a permanent peel and stick closure
  • Maximum clear gap between the inside edge of seam and edge of insert = 0.2″
  • Available in two sizes to hold booklets, mini catalogs, leaflets, and letters:
STOCK ALR – CLEAR BOOKLET ENVELOPE – 6″(h) x 10.5″(w) 17166 NO
direct mail envelopes

Premium ALR Envelope – Auto Insert

polybags and direct mail

For hand or machine inserting, with printed borders on one side to prevent a clear gap. This allows additional clearance as compared to the standard option.

The premium version is available with or without peel and stick tape.

direct mail envelopes and polybags
STOCK ALR – CLEAR BOOKLET ENVELOPE – 6″(h) x 8.25″(w) 17233 YES Peel and Stick Tape
STOCK ALR – CLEAR BOOKLET ENVELOPE – 6″(h) x 9.5″(w) 17167C YES Peel and Stick Tape
STOCK ALR – CLEAR BOOKLET ENVELOPE – 6″(h) x 9.5″(w) – No Tape 17304 YES Glue(not included)
  • This is a 100% clear mailing envelope made from USPS-approved polypropylene
  • Offers a permanent peel and stick closure
  • Available in four sizes for booklets, mini catalogs, leaflets and letters
  • Features a folded flap

Ultimate or Interactive Clear Poly Envelope

This version can be designed for that “wow” factor to create impact. It can be machine or hand-inserted and mails at the exact same postage as less impactful paper alternatives.

The ultimate version can be custom printed using single or full-color graphics and be made to “interact” with inserted contents. Special coatings and custom shapes and sizes are also available.

direct mail envelopes for polybags

How to get creative with an EnvyPak ALR poly envelope

New creative concepts make this already unique 100% clear, postage-approved poly envelope really stand out in the mailbox.

There are unique ways to create a design that “blends” the white bands required by the USPS. Here are two examples that do that in an artistic fashion.

direct mail envelopes for polybags

 “Futuristic” ALR poly envelope

EnvyPak envelopes with custom metallic print create a striking mail piece. Metallic PMS colors are available or we can print any PMS color on top of 877 silver. The silver shows through to create sheen.


This envelope uses white, 877 silver, blue/green gradient plus a white overprint for the copy and address block. The address block can be ink-jetted with solvent or UV ink.  It was machine inserted and sealed with glue.

Translucent Registration 

Think of an EnvyPak clear poly envelope as a blank canvas. Print used on the envelope can mask, compliment, highlight, or in the case of our sports car mailer, register with print on the insert.

This envelope was printed and converted inline on a Flexo press before the insert was printed. The insert’s graphics were then adjusted to properly register with print on the envelope.

This mailer was printed with low percentages of silver and white, using the four-color process. It was designed to have a bright effect that seems to pop off the envelope.

Yes, it looks good – but it also works. Here’s a summary of how one company used it successfully.

Case study summary – the EnvyPak ALR used for acquisitions

The Challenge

A distributor relied heavily on direct mail for new customer acquisitions. Their #10 control package featured a large clear window patch. Results tied to various traditional test mailings
did not yield higher ROI so they began searching for a solution with a highly unique look and feel.

Due to budget constraints, automation letter postage was a necessity.

The Approach

The client tested over 300,000 EnvyPak ALR (Automation Letter Rate) mailers at the end of Q3 2018. The mailer was designed to have a very official yet mysterious look to create intrigue. Custom graphics added to EnvyPak ALR’s unique look and feel, resulting in a one-of-a-kind mailer.

The Results

The EnvyPak test mailer doubled previous response rates.

While the EnvyPak envelope was more expensive than the previous control the increased response more than offset additional costs for a significant increase in ROI. A second, identical test mailing produced nearly identical results.

The EnvyPak ALR mailer is now the client’s monthly control package and has resulted in a substantial increase in first- time customers who are highly likely to become repeat buyers.

Frequently asked questions about EnvyPak clear poly envelopes

Q:  What does “Clear Gap” mean?

A:  A clear gap occurs when it is possible to see straight through both sides of the sealed envelope. When the insert shifts left or right inside the envelope a clear gap occurs if the leading and trailing edges leave more than a 2” gap between the edge of the insert and the edge of the envelope or border.

Q:  Why is the 11/16” paper strip required at the bottom of the EnvyPak?

A:  This paper strip is required so the USPS can inkjet a new barcode on this strip in the event that the address label IMB cannot be scanned during USPS sorting.

Q:  Is EnvyPak machine insertable?

A: Yes, most letter shops can machine insert EnvyPak envelopes. Free test kits are available upon request

Q: How many colors can be printed on an EnvyPak?

A: Up to 10 colors in total can be printed. This includes process, special match, and metallic inks.

Q: What is the price difference between paper envelopes and EnvyPak poly envelopes?

A: You can expect to pay more for a poly envelope but the comparison isn’t 1:1. The impression and the response rate give the EnvyPak a superior added value. Our repeat customers have shown that the increased response is worth the added cost.

Q: Is polypropylene really eco-friendly? Are biodegradable material options available?

A: Polypropylene (#5) is 100% recyclable but is dependent on local areas to accept the material for recycling. For a facility near you, visit Biodegradable polypropylene is available and is recognized as a fully recyclable #5 plastic.

About EnvyPak

EnvyPak, a division of, provides the best-looking and best-performing polypropylene products in the marketplace, and have been used by prestigious brands such as Mercedes-Benz, Citibank, Bass Pro Shops and more.

Contact EnvyPak at 16701 Square Drive, Marysville, OH 43040. Email:; or phone 877-835-3052.

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