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  • Heavy duty mailing bags made from 90 micron polythene
  • Almost double the thickness of regular polythene mailing bags
  • Made from co-extruded material, using several layers of film for tear-resistance - perfect for heavy or sharp items
  • Off-white outer and black inner so bags are 100% opaque
  • Peel and seal self-adhesive strip for fast and easy closure
  • Use with our range of multi-purpose labels
  • Please note, we have updated the print on these bags. You may receive a different print to the images.

Please note: these bags may or may not be printed with suffocation warning

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About heavy duty mailing bags

Heavy duty mailing bags are highly favoured by businesses looking to send heavy or sharp items through the post. They are also popular in mailing and dispatch industries, when sending bulky items such as catalogues and heavy pieces of literature.

Heavy duty mailing bags are manufactured from much tougher and durable polythene than standard mailing bags; this makes them more tear-resistant.

Kite’s range of heavy duty mailing bags

We stock six sizes of heavy duty mailing bags, all of which comply with Royal Mail’s PiP guidelines so that you can accurately calculate your mailing costs.

All our heavy duty mailing bags are co-extruded, which means several layers of film are extruded together to create a more durable bag.


  • Extra strong - Made from 90 micron (354 gauge) thick, co-extruded polythene
  • Lightweight - Great alternative to postal boxes
  • Opaque - White outer and black inner ensures these bags are 100% opaque, perfect for confidential items
  • Secure - Strong self-adhesive ‘peel and seal’ strip, on a 40mm lip. Allow the adhesive time to set for maximum performance.

Use these bags along with our range of multi-purpose labels.

recycling code 4
Click here for our recycling guide