• Co-Ex White Mailers
• Polythene Mailers - Blue
• Polythene Mailers - Grey
• Clear Poly Mailers

 

Bags / Mailing Bags

Mailing bags are designed to protect goods in transit while keeping packing time predictable and simple. This category focuses on lightweight, flexible mailers commonly used for eCommerce fulfilment, returns, internal distribution, and document despatch. The options here cover opaque co-extruded mailers for privacy, coloured polythene mailers for easy identification, and clear poly mailers where visibility is useful.

Bags / Mailing Bags — Helpful Guide

Choosing the right mailing bag is mainly about matching the film type and thickness to the item’s weight, shape, and the handling conditions it will face. Most mailing bags in this category are made from polyethylene film (often called “polythene”), valued for its low weight, moisture resistance, and tear performance. Many styles also use a peel-and-seal closure to speed up packing and reduce the need for tape.

Types of mailing bags in this category

• Co-Ex White Mailers — Co-extruded (multi-layer) opaque mailing bags designed to conceal contents and provide a robust outer layer for everyday parcel handling. The layered film structure is commonly used to balance toughness with flexibility, helping reduce splits at folds and corners.

• Polythene Mailers - Blue — Blue polythene mailers are useful when you want quick visual sorting (for example, by route, department, or service level). Like other poly mailers, they are lightweight and moisture resistant, making them suitable for soft goods and non-fragile items.

• Polythene Mailers - Grey — Grey polythene mailers are a common choice for general shipping where privacy is important. The darker film helps obscure the contents and can reduce the visibility of internal packaging, while still keeping overall parcel weight low.

• Clear Poly Mailers — Clear mailers allow the contents, paperwork, or internal labels to be seen without opening the bag. They are often used for documents, catalogues, printed materials, or situations where quick identification is needed. Because they are transparent, they are best for non-sensitive items.

What “co-ex” and “polythene” mean (in practical terms)

Polythene / polyethylene refers to a family of plastics widely used for flexible packaging films. In mailing bags, it is chosen for its combination of low weight, water resistance, and durability. In everyday use, “poly mailer” and “polythene mailer” typically describe the same kind of mailing bag.

Co-ex (co-extruded) film is made by combining multiple layers of film during manufacture. Each layer can be tuned for a specific job (for example, toughness, printability, or seal performance). In mailing bags, co-ex structures are commonly used to create an opaque outer layer with a strong, resilient feel.

Key features to understand before you choose

1) Opacity and privacy

If you ship clothing, personal items, or anything you’d prefer not to be visible in transit, choose an opaque mailer (such as white co-ex or grey/blue polythene). Opaque films help conceal the contents and can also reduce the chance of labels showing through from internal packaging.

2) Closure type (peel-and-seal)

Many mailing bags use a peel-and-seal adhesive strip. This speeds up packing and creates a consistent closure without extra tape. For best results, apply the seal to a clean, dry surface and press firmly along the full width of the flap to reduce the risk of lifting during handling.

3) Thickness (microns) and durability

Mailer thickness is often measured in microns (µm). As a simple reference, 1 micron equals 0.001 mm. Higher micron films generally provide better puncture resistance and tear strength, which matters for heavier items or parcels that may be dragged, stacked, or handled repeatedly.

• 35–50 µm: light-duty use (documents, very light soft goods).

• 50–70 µm: common general-purpose range for eCommerce soft goods.

• 70–100+ µm: heavier-duty use where extra puncture resistance is needed.

Thickness alone is not the only factor—film formulation and co-ex layering also influence performance—but micron guidance is a helpful starting point when comparing options.

4) Size and fit (avoid “overstuffing”)

Mailing bags perform best when the contents fit comfortably. Overstuffing increases stress at seams and corners and can cause the adhesive flap to sit under tension. As a rule, choose a bag that allows the item to lie flat with a little spare room for the flap to fold and seal without pulling.

5) Moisture resistance and weather exposure

Poly mailers are naturally moisture resistant, which helps protect contents from rain splashes and damp handling environments. If you ship paper goods or items sensitive to moisture, consider adding an inner protective layer (such as a document wallet or inner bag) to reduce risk from condensation or prolonged exposure.

How to choose the correct mailing bag (step-by-step)

1. Identify the item type: soft goods (t-shirts, textiles), documents/print, or mixed items. Soft goods typically suit poly mailers; documents may suit clear mailers if visibility is helpful.

2. Decide on privacy level: if you want concealment, choose opaque options such as Co-Ex White Mailers or Polythene Mailers - Grey. If visibility is required, choose Clear Poly Mailers.

3. Estimate handling stress: heavier items, sharp corners, or long courier networks generally benefit from thicker films and robust constructions. If parcels are frequently stacked or transported in bulk, extra puncture resistance can reduce damage rates.

4. Choose a practical size: measure the packed item (including any inner packaging). Select a bag that closes without stretching the film or forcing the flap to seal under tension.

5. Plan your labelling: ensure there is a smooth area for labels to adhere. For clear mailers, consider whether internal labels or paperwork should be visible; for opaque mailers, ensure the outer label is applied flat and firmly.

Packing tips that reduce damage and returns

Protect corners and edges

Even tough films can puncture if a sharp corner presses repeatedly during transit. For boxed items or products with hard edges, consider adding a thin protective wrap or using an inner carton before placing the item into a mailer. This spreads pressure and reduces point loads.

Remove excess air

Trapped air can make parcels bulky and more likely to snag on conveyor edges. Before sealing, gently press out excess air so the bag conforms to the contents. This also helps the adhesive flap sit flat and improves seal consistency.

Seal technique matters

Peel the release liner cleanly, align the flap carefully, and press firmly across the full width. Pay extra attention to the corners of the flap, where lifting can start. If packing in cold environments, allow the adhesive area to warm slightly for better bonding.

Consider double-bagging for high-risk items

For items that are prone to scuffing, or for shipments that may be exposed to rough handling, placing the product in an inner bag before the outer mailer can add abrasion resistance and reduce the chance of surface damage. This is especially useful for printed materials and textiles.

Case study: reducing packing time while improving parcel consistency

A small fulfilment team shipping apparel and accessories often faces two competing goals: pack quickly and keep parcels consistent for carrier acceptance. By standardising on a small set of mailer sizes and using peel-and-seal closures, packers can reduce time spent measuring tape and reworking closures. Opaque mailers help maintain customer privacy, while clear mailers can be reserved for internal transfers or document shipments where quick identification is needed.

In practice, the biggest improvements usually come from:

• Standardising sizes so packers don’t hesitate between too many options.

• Matching thickness to risk (light-duty for documents, heavier-duty for bulky or mixed items).

• Improving seal consistency with a simple checklist: clean surface, aligned flap, firm pressure.

Common use-cases and which type typically fits

• Clothing and soft goods: opaque mailers are often preferred for privacy. Consider Co-Ex White Mailers or Polythene Mailers - Grey.

• Warehouse sorting by colour: coloured options such as Polythene Mailers - Blue can help separate orders, routes, or departments at a glance.

• Documents, catalogues, and printed materials: where visibility helps, Clear Poly Mailers can simplify identification and reduce handling time.

• Returns and exchanges: choose a size that accommodates the original item without forcing it in. Clear instructions and a consistent sealing method can reduce leakage and damage during return transit.

Storage and handling best practices

Store mailing bags in a clean, dry area away from direct sunlight and heat sources. Excess heat can soften adhesives and affect sealing performance, while dust can reduce adhesion. Keep bags flat where possible to avoid creasing the flap area, which can interfere with a smooth seal.

Environmental and compliance considerations (practical overview)

Poly mailers are lightweight, which can reduce transport emissions per shipment compared with heavier packaging formats. However, local recycling rules vary. If you need to meet specific recycling or labelling requirements, check the guidance applicable to your region and the material specifications for the mailer type you select.