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Medium Duty Builders Roll
1 metre roll, unfolding to 2 metre wide sheeting. 400 gauge, 96m long (18 Kg Roll)
From £50.78 each
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Mailing Bags with Printed Designs
Mailing Bags with Printed Designs
An exclusive set of designer printed mailers in handy pack sizes.
Our Budget Grip Seal Bags are a cheaper thinner range of the handy resealable bags (with the option of write-on-panels to easy label and catalogue their contents)
Budget Grip Seal Bags
Ideal for sorting
and storing things!
In Grip Seal Bags...

Expandable Cardboard Envelope - Large

MCB04 Expandable Cardboard Envelope - Large
352mm wide x 249mm long (flat) / 312mm wide x 209mm long x 40mm deep (expanded)
Large Amazon-style solid paperboard envelope with expandable side gussets for simple conversion into a cardboard box. Also known as a capacity mailer or book mailer. 100% recyclable. Boxed in 50's.
Quantity: Cost? Add
Order Quantity No. in pack Price per pack Price per pack Price per 1000
(Inc. VAT) (Ex. VAT) (Ex. VAT)
50+ 50 £20.21 £16.84 £336.80
250+ 50 £18.20 £15.16 £303.20
500+ 50 £17.10 £14.25 £285.00
1000+ 50 £13.38 £11.15 £223.00
 

Large expandable cardboard mailer - product features

  • An innovative and shape-shifting postal solution.
  • Easily switch between a flat envelope and a full box, or any intermediate form.
  • Quick and secure sealing with the peel & seal strip, and rapid opening with the rip-strip.
  • Durable, non-corrugated cardboard offers robust, lightweight protection.
  • Suitable for a wide range of retail and e-commerce businesses.
  • Adjustable dimensions to provide a custom fit for your products.
  • Gusset expansion increases depth while adjusting width and/or length.
  • Ideal for shipping larger items efficiently through mail or courier.
  • Often called a capacity mailer, book mailer, or book box.
  • Complies with Royal Mail's 'Large letter' or 'Small parcel' size specifications - see below.
  • Fully recyclable, making it a sustainable packaging choice.

Large expandable cardboard mailer - dimensions when flat

  • Width: 352mm (14")
  • Length: 249mm (10")

Large expandable cardboard mailer - dimensions when expanded

  • Width: 312mm (12.5")
  • Length: 209mm (8")
  • Depth (gusset): 40mm (1.5")

Royal Mail Pricing in Proportion sizing - Large expandable mailer

This solid board envelope comes in at the following sizes on Royal Mail's Pricing in Proportion (PiP) scale:

  • Size when flat: Large letter
  • Size when expanded: Small parcel

See more sizes in this range

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Polybags Ltd is ranked #1 when compared to all other companies in TrustPilot's category "Packaging". See a live feed of more independent Google & Trustpilot reviews here.

Grip Seal Bag with Write-On Panel - Mini
76mm wide x 83mm long, 50 micron thickness
From £14.74 per 100
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100%-Recycled Mailing Bags
Bio and 100%-recycled mailing bags in low quantity handypacks.
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