Polythene Mailers - Grey 250G
Grey Opaque Poly Mailers (No.5) — Durable, Professional Postal Packaging
These grey opaque polythene mailers are designed for fast, reliable dispatch of non-fragile items where a clean presentation and privacy in transit matter. The opaque grey film helps conceal contents, while the integrated flap provides a straightforward close-and-seal workflow for busy packing benches. Commonly used across eCommerce, fulfilment, mail order and internal distribution, poly mailers are a practical alternative to boxes for soft goods and other items that don’t require rigid protection.
This listing covers a configurable range within the same product family (often supplied in multiple pack quantities). Please select the option that best suits your packing volume and workflow.
Key Features
Opaque grey film (privacy in transit):
Helps reduce visibility of the contents during handling and delivery, supporting a more discreet customer experience.
Lightweight mailing solution:
Polythene mailers add minimal weight compared with cartons, helping keep postage costs efficient while still providing a protective outer layer.
Integrated flap closure:
Designed for quick sealing during packing. Ideal for high-throughput environments where speed and consistency are important.
Water-resistant outer layer:
Polythene provides a barrier against light rain and splashes encountered in typical courier networks, helping keep goods cleaner in transit.
Tear and puncture resistance:
Suitable for everyday shipping of soft goods and other non-fragile items, offering better durability than paper envelopes in many dispatch scenarios.
Space-saving storage:
Supplied flat, these mailers store efficiently and are easy to stage at packing stations.
- Opaque grey for discreet shipping
- Polythene construction for lightweight protection
- Flap closure for fast packing
- Water-resistant outer layer for typical transit conditions
- Flat-packed for easy storage and handling
Typical Uses
- Clothing and fashion items (t-shirts, hoodies, trousers, dresses)
- Soft accessories (scarves, hats, socks)
- Textiles and home soft goods (linen, towels, bedding)
- Non-fragile boxed items that benefit from an additional outer wrap
- Returns and exchanges (including pre-labelled return workflows)
No.5 Grey Opaque Poly Mailers — Full Product Guide
Choosing the right poly mailer is about balancing presentation, protection, packing speed and postage efficiency. The No.5 grey opaque mailer format is commonly selected when you need a larger mailer size within a standard range, with a flap that supports quick sealing and a film thickness intended for everyday dispatch.
How It Works
Poly mailers are simple by design: place the item inside, remove excess air for a neat parcel, fold the flap over and seal. For best results, match the mailer size to your product so there is enough room for easy insertion without leaving excessive empty space. A snug fit improves presentation and reduces the chance of snagging during handling.
Packing tip: If you ship garments, consider folding consistently and using a packing slip pouch or internal document wallet where required by your process. For premium presentation, many shippers place the product in tissue or an inner bag before inserting into the mailer.
Materials and Construction
These mailers are made from polythene film and supplied in an opaque grey finish. Polythene is widely used for mailing bags because it is lightweight, flexible and resistant to moisture. The film thickness (micron) is a key indicator of robustness; thicker films generally provide improved puncture and tear resistance for demanding distribution environments.
Understanding micron (mic):
Micron is a measure of film thickness. When comparing mailers, ensure you compare like-for-like thickness and size, as both affect performance and suitability.
Size and Fit Guidance
This product family is commonly referenced by a “No.” size and may also show dimensions in both inches and millimetres, sometimes with an added flap measurement (shown as “+” in the size). The “+” portion typically refers to the flap depth used for sealing.
- Main dimensions: the usable body of the mailer for your product
- Flap allowance: additional length for folding and sealing
Fit tip: If your items are bulky (e.g., thick hoodies or multiple garments), allow extra room so the seam and flap are not under strain. If you ship flatter items, a closer fit can improve appearance and reduce movement inside the parcel.
Protection and Transit Performance
Poly mailers are best suited to items that do not require rigid protection. They provide a protective outer layer against scuffs, light moisture and general handling. For fragile goods, consider using a box or adding internal protection (e.g., bubble wrap) before placing inside a mailer, depending on your shipping method and carrier requirements.
Floor Type Compatibility (Packing Bench & Warehouse Use)
Because these mailers are supplied flat, they work well in most packing environments:
- Bench packing: easy to stack and grab quickly
- Pick/pack stations: can be stored in bins or vertical dispensers
- Mobile packing trolleys: lightweight and space-efficient
Health and Safety
As with all plastic packaging, keep mailers away from babies and young children due to suffocation risk. In warehouse settings, keep stacks tidy to reduce slip/trip hazards and avoid placing loose mailers on walkways. Use appropriate cutting tools carefully if opening returned parcels.
Ideal Applications and Use Cases
eCommerce fulfilment: A popular choice for apparel and soft goods where speed and postage efficiency are priorities.
Mail order and subscription shipments: Suitable for repeatable packing processes and consistent parcel presentation.
Returns processing: Useful for sending replacement items or providing customers with a simple return packaging option (where your process supports it).
Internal distribution: Helpful for moving items between sites or departments while keeping contents clean and contained.
Maintenance, Cleaning and Care
Poly mailers are single-use shipping packs in most workflows. Store them in a clean, dry area away from direct heat sources and prolonged sunlight to help maintain film performance. Keep cartons closed until needed to reduce dust and improve packing station hygiene.
Case Study (Example Workflow)
A growing apparel retailer dispatching daily orders can streamline packing by staging poly mailers at each bench, pre-printing labels, and using a consistent fold method for garments. The opaque grey finish supports discreet delivery, while the lightweight format helps keep shipping costs predictable. For higher-value items, the retailer can add an inner branded bag or tissue wrap to elevate unboxing without switching to cartons.
Who Is It For?
- Online sellers shipping clothing, textiles and other non-fragile items
- Fulfilment centres needing fast, repeatable packing steps
- Businesses looking for a discreet, professional-looking outer pack
- Operations aiming to reduce storage space compared with boxes
Colours / Features Available
This listing is for grey opaque polythene mailers. Opaque mailers are commonly chosen for privacy and a clean, uniform appearance across shipments.
Sizes Available
This product is part of a numbered size range (No.5) and is typically shown with dimensions in both inches and millimetres, including a flap allowance (the “+” measurement). Please refer to the selected variant options on this page for the exact size and pack quantity available for your chosen configuration.
Referenced sources used for structure and cross-checking:
Sapphire category listing for grey polythene mailers: https://store.sapphirepackaging.com/collections/bags-mailing-bags-polythene-mailers-grey
Comparable grey opaque mailer ranges (different thicknesses): https://tecpackaging.co.uk/product-catalogue/postal-products/polythene-mailing-bags-various-colours/ and https://www.odlpackaging.co.uk/media/wysiwyg/offline-products.pdf