Few things disappoint a customer more than a bent print, a creased certificate or a photo with a crack across the corner. Flat items look tough, but they're surprisingly easy to damage in the post.
The good news is that choosing the right envelope solves almost every problem. In this guide we compare the three most popular options for flat items: rigid card mailers, eFlute corrugated envelopes and bubble padded mailers.
The Quick Answer
| Rigid mailer (700gsm card) | eFlute rigid envelope | Bubble mailer | |
|---|---|---|---|
| Stops bending | Very good | Excellent | Poor |
| Cushions impacts | Low | Medium | Good |
| Thickness of contents | Thin (paper, prints) | Thin to moderate (prints, books, records) | Thin to bulky (small goods) |
| Weight | Light | Light to medium | Very light |
| Recyclable | Yes, paper stream | Yes, paper stream | Depends on type |
| Best for | Prints, photos, certificates, cards | Large prints, artwork, books, vinyl records | Small items that need cushioning, not flatness |
In short: if the item must stay flat, choose a rigid mailer or eFlute envelope. If it needs cushioning more than stiffness, choose a bubble mailer.
Rigid Mailers (700gsm Card)
Rigid mailers are envelopes made from heavy 700gsm paperboard. They feel like a thick, stiff card and are designed to resist bending in sorting machines and mail bags.
Pros
- Very stiff for their weight, so they keep paper items flat
- Smooth white surface that looks clean and professional and is easy to label
- Slim profile that often qualifies for cheaper letter or large letter rates
- Recyclable with paper and cardboard
Cons
- No cushioning, so not suitable for anything breakable
- Limited room for thicker contents
Best for
Art prints, photographs, certificates, greeting cards, stickers, posters that can be sent flat, and important documents.
Sizes
- A5 rigid mailer, 170 x 230mm
- A4 rigid mailer, 240 x 330mm
- A3 rigid mailer, 330 x 450mm (also available with a "Handle With Care" print)
eFlute Rigid Envelopes (Corrugated Cardboard Envelopes)
eFlute envelopes are made from thin corrugated cardboard, the same material as many mailing boxes but with a very fine flute. That wavy inner layer makes them much stiffer than flat card and gives a little cushioning at the edges. If you'd like to understand flute types, see our guide to corrugated flutes.
Pros
- The strongest bend resistance of the three options
- Extra edge and corner protection
- Wide range of sizes, including A2 for large artwork
- Recyclable and plastic-free
Cons
- Slightly heavier and thicker than 700gsm card, which can affect letter-rate eligibility
Best for
Larger prints and artwork, canvas boards, books, calendars, vinyl records, and anything valuable that absolutely mustn't bend.
Sizes
- A5, 170 x 230mm
- A4, 240 x 330mm
- A3, 330 x 450mm
- A2, 450 x 630mm
- Sizes made to fit inside AusPost prepaid envelopes: DL, C5 and C4
- 12 inch LP and 7 inch vinyl record mailers
Brown kraft is the most popular finish, and white and black versions are available in several sizes for a more premium look. See all eFlute rigid envelopes.
Bubble Mailers (Padded Envelopes)
Bubble mailers have a layer of bubble wrap bonded to the inside of a paper or poly outer. They're excellent at absorbing knocks, but they're soft and flexible, so they won't stop a flat item from bending.
Pros
- Built-in cushioning without extra wrapping
- Very light, which keeps postage down
- Poly bubble mailers are water-resistant
- Lots of sizes and colours
Cons
- No stiffness, so prints, photos and documents can still bend
- Mixed materials can be harder to recycle (kraft paper versions are a greener choice)
Best for
Small items that need protection from knocks: jewellery, cosmetics, phone accessories, USB drives, small electronics, keys and spare parts.
Options
- White poly bubble mailers, black and pink
- Kraft paper bubble padded envelopes
- Premium metallic bubble mailers
Which Should You Choose? Common Examples
- A4 art print: A4 rigid mailer, or an A4 eFlute envelope for limited editions and higher-value prints.
- A3 or A2 poster you don't want to roll: A3 or A2 eFlute envelope. For larger rolled posters, see our long mailing boxes.
- Photographs: rigid mailer, with each photo in a clear sleeve to protect the surface.
- Certificates and legal documents: rigid mailer, so they arrive flat enough to frame or file.
- Paperback books: eFlute envelope, or a book wrap mailer for thicker books. See our guide to shipping books.
- Vinyl records: a dedicated eFlute vinyl record mailer.
- Jewellery or cosmetics: bubble mailer.
- Trading cards: top loader inside a rigid mailer for stiffness, or a bubble mailer for small, thick bundles.
Tips for Posting Flat Items
- Choose a mailer slightly bigger than the item. Allow around 10 to 20mm on each side so the edges don't get crushed.
- Add a stiffener for valuable items. A sheet of card or an extra layer behind the print gives another line of defence.
- Protect surfaces. Slip prints and photos into a clear cello or poly sleeve to prevent scuffs and moisture marks.
- Mark the parcel. "Do Not Bend" or "Handle With Care" won't guarantee careful handling, but it helps.
- Check postage size limits. Thickness and weight affect which AusPost rate applies. Our AusPost packaging requirements guide covers the details.
Shop Mailers for Flat Items at eBPak
Whether you're an artist sending prints, a photographer delivering orders or a business posting important documents, we have a mailer to suit. Browse our 700gsm rigid mailers, eFlute rigid envelopes and bubble padded envelopes, all available in packs and wholesale quantities.