Polythene Mailers - Grey 250G
No.3 Grey Opaque Poly Mailers (13 x 19 in + flap) — Secure, Lightweight Mailing Bags
These grey opaque polythene mailers are designed for fast, reliable despatch of non-fragile items where privacy, weather resistance and efficient packing matter. The opaque grey film helps conceal contents in transit, while the lightweight construction keeps postage weight down compared with boxes. This listing covers the No.3 format (commonly referenced as 13 x 19 inches with a flap), supplied as peel-and-seal style mailing bags for straightforward, high-throughput packing.
Key Features
Opaque grey film (privacy in transit):
Grey opaque material helps prevent the contents being seen during handling and delivery, supporting discreet shipping for clothing, soft goods and general merchandise.
Peel-and-seal closure (quick packing):
A pressure-sensitive peel-and-seal strip enables consistent sealing without tape, speeding up fulfilment and reducing packing consumables.
Lightweight, space-saving packaging:
Poly mailers store flat and take up minimal warehouse space, helping streamline packing benches and storage compared with rigid packaging.
Moisture-resistant outer layer:
Polythene provides a barrier against rain splashes and damp conditions encountered during distribution, helping protect contents in typical courier networks.
Strong film for everyday despatch:
This product is specified at 55 micron thickness, offering a practical balance of durability and flexibility for routine shipping of non-breakable items.
- Product type: Grey opaque polythene mailers
- Common size reference: No.3 (13 x 19 in + flap)
- Metric size reference: 325 x 475 mm + 50 mm flap
- Film thickness: 55 micron
Typical Uses
- Clothing and textiles (t-shirts, hoodies, uniforms, soft accessories)
- Soft goods and non-fragile retail items
- Printed materials where moisture resistance is helpful (catalogues, brochures)
- E-commerce fulfilment and returns (where a quick seal is required)
- Warehouse-to-store transfers for baggable items
No.3 Grey Opaque Poly Mailers — Full Product Guide
Choosing the right mailing bag is about matching the bag format to your packing workflow and the protection level your products need. Grey opaque poly mailers are a popular choice for businesses that ship high volumes of soft or non-fragile items and want a clean, professional presentation with discreet coverage of the contents.
How It Works
Pack the item into the mailer, remove the release liner from the peel-and-seal strip, then fold the flap down firmly to create a secure closure. For best results, press along the full width of the seal to ensure consistent adhesion. Once sealed, the bag forms a lightweight outer pack suitable for standard courier and postal networks.
Materials and Construction
These mailers are made from polythene film specified at 55 microns. The grey opaque finish is intended to reduce visibility of the contents. Poly mailers are flexible and conform around the product, which helps reduce void space and can improve packing efficiency for soft items.
Size and Fit Guidance
This listing is commonly referenced as No.3 and described as 13 x 19 inches + flap (also shown as 325 x 475 mm + 50 mm flap). When selecting a mailer size, allow room for the product thickness and any internal packaging (such as tissue, inner bags, or paperwork). If you are packing bulky textiles or multiple items per order, consider stepping up to the next size to avoid overfilling and to maintain a reliable seal.
Protection and Performance in Transit
Poly mailers are designed primarily for non-fragile goods. They provide a moisture-resistant outer layer and help protect against scuffs and light handling marks. For items that can be crushed or require impact protection, consider using an internal protective layer (e.g., bubble wrap or a padded mailer) or switching to a rigid carton.
Health and Safety
- Keep packaging away from babies and small children to avoid suffocation risk.
- Use appropriate manual handling practices when packing high volumes.
- Ensure the work area is clear so the peel-and-seal liner is removed and disposed of safely.
Ideal Applications and Use Cases
E-commerce fulfilment:
Ideal for pick-pack operations shipping apparel, soft accessories and general merchandise where speed and consistency are important.
Returns and exchanges:
Useful for returns workflows where a simple, reliable seal helps reduce rework and tape usage.
Warehouse distribution:
Suitable for internal transfers of baggable items between sites or to retail locations.
Maintenance, Cleaning and Care
Poly mailers are single-use shipping packs and do not require maintenance. Store them in a clean, dry area away from direct sunlight and excessive heat to help preserve adhesive performance and film condition. Keep cartons closed until use to reduce dust contamination on the seal area.
Packing Tips for Best Results
- Don’t overfill: Overstuffing can stress seams and reduce seal reliability.
- Seal on a clean surface: Dust or fibres on the flap area can affect adhesion.
- Press firmly across the full seal: Apply even pressure end-to-end.
- Use an internal document pouch if needed: If you need paperwork visible externally, use a dedicated document enclosed wallet rather than placing documents loose inside.
Case Study (Example Workflow)
A clothing retailer shipping daily orders uses grey opaque poly mailers to reduce packing time and keep parcels discreet. Pickers place folded garments with a packing slip inside the mailer, remove the peel strip, seal, and apply the shipping label. The flat-packed mailers reduce storage space at the packing bench, and the moisture-resistant outer layer helps protect orders during doorstep delivery.
Who Is It For?
- Online retailers shipping clothing, textiles and other non-fragile items
- Fulfilment centres looking to speed up packing and reduce tape usage
- Businesses wanting discreet, opaque packaging for customer privacy
- Operations that need lightweight packaging to help manage shipping costs
Colours / Features Available
This product is part of the grey opaque polythene mailer range. The key feature is the opaque grey film designed for privacy in transit, combined with a peel-and-seal closure for quick packing.
Sizes Available
Sapphire product pages may represent multiple variants within a range. This listing is the No.3 format, commonly referenced as 13 x 19 inches + flap (also shown as 325 x 475 mm + 50 mm flap). If you need a different fit for your products, check the available variant options within the grey poly mailer range.
Note: Specifications shown above are taken from the product listing and matching supplier references for the same No.3 grey opaque poly mailer format (55 micron; 325 x 475 mm + 50 mm flap).