Shop Lightweight Mailers

Save Up to 50% on Shipping Cost

With Conformer Lightweight Mailers you can save more by shipping your apparel and other merchandise as USPS Automated Flats.

Mail your apparel and accessories and save big

Conformer lightweight mailers allow you to send your small merchandise as USPS Automated Flat-Sized Mail instead of Parcels. This results in substantial savings.

Conformer Lightweight Mailers are perfect for apparel including t-shirts, socks, bathing suits, and intimate apparel as well as solid merchandise including toiletries, supplements, jewelry, cables, and more.

  USPS Lightweight Parcel
(4 oz.)
USPS Flat in a Best Mailer
(4 oz.)
Rate $4.04 $2.07
Tracking Delivery confirmation included (Required for Amazon, eBay, Etsy, Walmart) No delivery confirmation.  Informed Visibility Mail Tracking is available.
Time in transit 3-5 days 5-8 days
apparel and accessories

What is USPS Flat?

Simply put, USPS flat is flat sized mail.

  • Not Larger than 12″ x 15″
  • Not more than 3/4 Inch Thick
  • Flexible
  • Uniformly Thick

Many items that are shipped as parcels in polybags, bubble mailers, or boxes could qualify for USPS Flat Mail rates with the right packaging.

Why Best Mailers qualify as USPS Flats, and other packaging options don’t

Poly bags allow contents to shift from side to side. Poly Bags do not stay flat, or have a uniform thickness. Poly Bags do not qualify for USPS Flats and must ship as Lightweight Parcels.
Too Thick and Rigid. Boxes don’t offer the flexibility required for USPS Flat. Boxes must ship as lightweight parcels.
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Bubble Mailer
USPS Flats must be less than ¾” thick. Bubble mailers add unnecessary thickness, and do not stop contents from shifting. Does not qualify for USPS Flat-rate mail.
Designed to start flat and stay flat. These mailers do not expand to fit garments and are difficult to keep merchandise flat while inserting.
Conventional Paperboard Mailer
paperboard mailer

Introducing Conformer Lightweight Mailer

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Uniform Thickness

Conformer Lightweight mailer prevents bumps or protrusions leaving less than 1/4″ variance in thickness.

Flexible Design

Designed to bend. Conformer Lightweight mailer meets USPS minimum flexibility requirements for Flats.

Contents Stay Secure

Merchandise will not shift once in place. Keeping the package uniform in thickness and preventing contents from bursting out.


3 features work together to create a best-in-class mailer

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Curious if your product would qualify?

Speak with a Conformer Packaging expert today to learn more about USPS Flat requirements and how your merchandise can qualify.

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Save More Than Just Shipping Cost

Save The Environment

Eco-Friendly design that is 100% paper, 100% recyclable, & 100% Compostable.

Save Time

Design for Efficient Fullfilment. Self seal closure saves you minutes per box. See for yourself.

Save Space

Save up to 75% on storage space when compared to Bubble Mailers.

Case Study

America's largest selection of heirloom vegetable seeds offering free shipping within the US.

3 Made-to-order mailer sizes
Designed to ship 1 to 21 seed packets as a USPS Automated Flat
Bubble mailer shipped as a Parcel $3.88
Conformer Mailer shipped as a Flat
Postage Savings
Packages shipped in test phase
Test phase savings
Lightweight Small

Outside Dimension
7 3/8″ X 9 5/8″

Best for mailing
Accessories, underwear, socks

Lightweight Medium

Outside Dimension
10″ X 13″

Best for mailing
T-shirt (up to size L)

Lightweight Large

Outside Dimension
12″ X 15″

Best for mailing
T-shirt (XL and XXL)

Inside dimension 6 ½” x 8 ½” Inside dimension 9” x 12” Inside dimension 11” x 14”
Capacity (expands up to) 3/4” Capacity (expands up to) 1″ Capacity (expands up to) 1″
Gauge 15 pt Gauge 15 pt Gauge 15 pt
Weight per unit 1.2 oz Weight per unit 1.7 oz Weight per unit 2.5 oz
Mailer per Carton 250 Mailer per Carton 250 Mailer per Carton 150
Cartons per skid 75 Cartons per skid 40 Cartons per skid 40
Mailers per skid 15,000 Mailers per skid 10,000 Mailers per skid 6,000
Buy Now Buy Now Buy Now

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Contact us

44 South Bayles Ave., Ste. 205
Port Washington, NY 11050

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Copyright © 2020 Conformer Products, Inc.. All rights reserved. CONFORMER® is a registered trademark of Conformer Products, Inc.
U.S. Pat. Nos.: 8,162,204 : 8,215,537 : 8,684,259 : 8,215,619 : 8,215,345 : 9,352,879. Canadian Pat. Nos. 2,418,571: 2,554,473 : 2,641,639. Other Patents Pending.

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