Grey Mailing Bags 9×12" (229×305 mm) – Self-Seal Recycled Postal Bags
Grey Mailing Bags 9×12" (229×305 mm) – Self-Seal Recycled Postal Bags
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Grey Mailing Bags 9×12" (229×305 mm) – the smart A4-friendly choice for daily post
Grey mailing bags 9×12" (229×305 mm) are a top pick for UK sellers who send A4 items and small soft goods every day. This size fits A4 with room for padding or a folded garment, while keeping weight low. Made from tough 60-micron LDPE, these self-seal postal bags close in seconds, are moisture-proof (water-resistant in wet weather), and the opaque grey film protects privacy from warehouse to doorstep.
Why this 9×12" size works so well
It’s compact, neat, and cost-effective. 9×12" is larger than A4 (210×297 mm), so you can slide in documents, brochures, and slim boxes without forcing the seal. It is also ideal for single T-shirts, kids’ clothing, light accessories, and beauty items in retail cartons. The footprint stacks cleanly in mail sacks and totes, which helps keep your packing area tidy and your dispatch fast.
Who it’s for
- Apparel & merch: single T-shirt, thin jumper, gym top, headwear, scarf, socks, small bundles.
- Beauty & wellness: boxed skincare, cosmetics palettes, hair accessories, nail kits.
- Stationery & print: A4 brochures, photo books, documents in wallets, diaries, planners.
- Craft & hobby: small fabric cuts, patterns, kits, components in inner sleeves.
- Marketplace sellers: quick, tidy packaging for high-turnover A4 orders.
Fit & packing guidance
- Best fit: A4 documents in a wallet, single T-shirt, thin jumper, boxed cosmetics, diaries, planners.
- If it feels tight: step up to 10×14" for thicker books or padded clothing.
- If it feels roomy: use a simple inner sleeve or fold once for a flatter parcel.
- Corner care: round or pad the corners of inner boxes to reduce punctures.
- Press out air: squeeze air before sealing so labels sit flat and postage stays low.
Key benefits
- Self-seal strip: fast, tamper-evident close for busy benches.
- 60-micron co-extruded film: helps resist scuffs, splits and rough handling.
- Moisture-proof / water-resistant: protection against rain and splashes in transit.
- Opaque grey: clean, professional look and contents privacy.
- Lightweight: reduces parcel weight vs small cartons.
- Recyclable LDPE: remove the glue strip before recycling.
Specifications
| Spec | Value |
|---|---|
| Size (inches) | 9 × 12" |
| Size (mm) | 229 × 305 mm |
| Thickness | 60 µm |
| Material | LDPE (Low-Density Polyethylene) |
| Closure | Peel-and-seal, tamper-evident |
| Colour | Grey, opaque |
| Water protection | Moisture-proof / water-resistant |
| Recyclability | Recyclable – remove glue strip before recycling |
Eco & Materials
Material: 100% recycled LDPE (resin code 4), co-extruded for extra strength and opacity. Recyclable in many UK schemes — please remove the adhesive strip first. These bags are not biodegradable or compostable.
Strength & Protection
60-micron co-extruded film is puncture- and tear-resistant and moisture-proof. The self-seal, tamper-evident all-season adhesive creates a permanent bond once pressed, helping contents stay secure from dispatch to delivery.
Storage & Performance
Store bags at 13–21 °C and out of direct heat or sunlight. Let cold stock acclimatise to room temperature before use to keep adhesive performance high.
Lightweight = Lower Postage
Our recycled LDPE mailers are exceptionally lightweight, helping you keep parcels in lower weight bands versus boxes — a simple way to cut postal costs without losing protection.
Size comparison (pick the best fit for each order)
| Size | Inches | Millimetres | Typical fit |
|---|---|---|---|
| Smaller option | 6 × 9" | 152 × 229 mm | Small accessories, cosmetics, A5 packs |
| This page | 9 × 12" | 229 × 305 mm | A4 with room, single tee, boxed cosmetics |
| Larger option | 10 × 14" | 254 × 355 mm | Books, thicker apparel, A4 bundles |
If you often ship mixed sizes, keep both 10×14" and 9×12" on your bench so staff can choose the best fit. For bulkier items, move up again to 12×16".
Packing tips to save time and reduce damages
- Use a light inner sleeve for dusty or powder-prone items.
- Fold garments flat; avoid hard folds that create sharp corners.
- Apply labels on a smooth area and press firmly for reliable scanning.
- For returns paperwork, use a clear document wallet outside the bag.
FAQs
Does 9×12" fit A4?
Yes — it’s larger than A4 (210×297 mm), leaving room for a wallet or sleeve.
Are these bags moisture-proof?
Yes. The co-extruded recycled LDPE is moisture-proof and water-resistant in wet conditions. For very wet routes, add an inner sleeve.
Are they recyclable or biodegradable?
They are recyclable in many UK schemes — please remove the glue strip first. They are not biodegradable or compostable.
What thickness is this size?
This 9×12" bag is produced at 60 µm for strength with low weight.
How should I store them?
Keep stock between 13–21 °C and out of direct heat/sunlight. Let cold packs acclimatise before use.
Build a complete packing setup
Team these grey mailing bags 9×12" with packaging tape for any inner cartons, Document Wallets for paperwork, and cardboard boxes when rigid protection is needed. For more colours and sizes, visit the full Mailing Bags collection.
Royal Mail 24 Tracked
Dispatched same day if ordered before 5 pm Monday to Friday. Please allow up to 1-2 days for delivery.
£1.99
DPD Next Day
Dispatched same day if ordered before 3 pm Monday to Thursday. Not available to Scottish Highlands & Islands.
£4.99
Free on orders over £100