Description
220 x 160 x 16mm Black Superflat Letter Gauge Mailer B278 - Superflat Mailing Box
This Superflat Mailing Box offers a compact and environmentally conscious shipping solution, measuring 220 x 160 x 16mm with a sophisticated black exterior.
- 220 x 160 x 16mm dimensions provide a slim profile for mailing flat items.
- Sleek black finish offers a professional and modern aesthetic for your shipments.
- Crafted from Kraft corrugated cardboard, featuring over 50% recycled fiber content for reduced virgin material use.
- FSC Certified, ensuring materials are sourced from responsibly managed forests.
- 100% recyclable and compostable, offering an eco-friendly end-of-life option.
Designed to minimize waste compared to traditional packaging, this mailer utilizes a die-cut folding format that optimizes material usage and supports circularity, setting a higher standard for sustainable shipping.
Key Technical Advantages: Sustainability and Performance
- Lay the flat box printed side down and fold up the side walls.
- Fold the side flaps in so the box holds its shape.
- Slide in your flat item: prints, cards, photos, a scarf or a folded tee.
- Close the lid and tuck the front flap into the front of the box.
- For extra security, seal the front flap with a strip of tape or a branded sticker.
- Free delivery to Sydney & Melbourne metro on orders over $500.
- $50 flat rate to Wollongong areas and $75 to Gosford & Newcastle areas (up to 2 tonne).
- Australia-wide delivery via Australia Post and trusted couriers.
- Free pickup from Minto NSW or Braeside VIC, Mon–Fri 9am–4pm.
- 90-day returns on unopened items. See our refund policy.
Payment & Security
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.

Sizing
What fits in this box
Inside: 220 x 160 x 16mm (length x width x height)
- A5 notebooks, cards and small books lie flat
- Slim 16mm profile for flat items: prints, cards, photos, scarves and folded tees
- About 0.6 litres of space inside
- Delivered flat, folds into shape in seconds
- Sizes are inside measurements. Allow 5–10mm each side for tissue paper or bubble wrap.
- Not sure? Use the size finder below or call us on (02) 8750 5347.
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Packing essentials
















Buying in bulk? Pay less per box.
Order 1,000+ mailing boxes, or Australian-made shipping cartons by the pallet, and we'll quote a wholesale price. Trade accounts get invoice terms and a dedicated contact.
Questions about this box
What can I send in a superflat box?
Superflat boxes are about 16mm high inside, made for flat items: art prints, cards, photos, stickers, scarves, folded t-shirts, books and documents. They protect corners better than an envelope and stay thin and light to post.
Is the size inside or outside the box?
All sizes are internal (length x width x height), measured inside the box. The outside is a few millimetres bigger because of the board thickness.
How do I close the box?
Fold the box into shape, slide your item in, then close the lid and tuck the front flap into the front of the box. For extra security, seal the front flap with a strip of tape or a branded sticker.
Can I get this size in other colours?
Most superflat sizes come in white, brown, black, light blue and rose pink. Use the "Same size, other colours" link above the description to see every colour in this size.
Are the boxes delivered flat?
Yes. The boxes are delivered flat in packs and fold into shape in seconds, so they take up very little shelf space.
Can I print my logo on the box?
Yes. We make custom printed boxes from 1,000 units, usually in around 2 weeks. Get a quote. For smaller runs, a printed sticker or stamp on a plain box works well.
What does the pack size mean?
The pack size is how many boxes come in one pack, for example x100 is a pack of 100 boxes. "Number of packs" sets how many packs you get, so x100 with 2 packs is 200 boxes.
Can I return the boxes, or pick up my order?
Yes to both. We offer 90-day returns on unopened items (see our refund policy), and you can choose pickup at checkout and collect from Minto NSW or Braeside VIC, Monday to Friday 9am to 4pm.
Need it today? Pick it up.
Order online and we'll usually have it ready in 15–30 minutes at either warehouse.
























