---
product_id: 51250158
title: "Triplast 10 x A3 C3 Manilla Hard Board Back Envelopes (457x324mm) - Cardboard Backed Mailers with Peel & Seal Strip - Rigid Do Not Bend Envelopes for Mailing Posting Shipping & Storing Documents"
brand: "triplast"
price: "HK$331"
currency: HKD
in_stock: true
reviews_count: 8
category: "Triplast"
url: https://www.desertcart.hk/products/51250158-triplast-10-x-a3-c3-manilla-hard-board-back-envelopes
store_origin: HK
region: Hong Kong
---

# 457x324mm perfect A3 fit Peel & seal secure closure 1000 micron rigid board back Triplast 10 x A3 C3 Manilla Hard Board Back Envelopes (457x324mm) - Cardboard Backed Mailers with Peel & Seal Strip - Rigid Do Not Bend Envelopes for Mailing Posting Shipping & Storing Documents

**Brand:** triplast
**Price:** HK$331
**Availability:** ✅ In Stock

## Summary

> 📬 Elevate your mail game—because your documents deserve VIP treatment!

## Quick Answers

- **What is this?** Triplast 10 x A3 C3 Manilla Hard Board Back Envelopes (457x324mm) - Cardboard Backed Mailers with Peel & Seal Strip - Rigid Do Not Bend Envelopes for Mailing Posting Shipping & Storing Documents by triplast
- **How much does it cost?** HK$331 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.hk](https://www.desertcart.hk/products/51250158-triplast-10-x-a3-c3-manilla-hard-board-back-envelopes)

## Best For

- triplast enthusiasts

## Why This Product

- Trusted triplast brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Eco-Chic Packaging:** 100% recycled, biodegradable, and kerbside recyclable—mail with a conscience.
- • **Cost-Savvy & Lightweight:** Sturdy yet light design reduces postage costs without compromising protection.
- • **Flat & Flawless Delivery:** Rigid 120gsm kraft front + 1000 micron board back keeps documents crease-free and pristine.
- • **Seal the Deal in Seconds:** Built-in peel & seal strip ensures fast, hassle-free, and tamper-proof packing every time.
- • **Bold 'Do Not Bend' Warning:** Large red print deters careless handling, safeguarding your valuable contents.

## Overview

Triplast's 10-pack of A3 C3 manilla hard board envelopes combines robust 1000 micron rigid backing with a 120gsm kraft paper front to protect flat documents like posters and blueprints. Featuring a peel & seal strip for quick, secure closure, these eco-friendly, lightweight mailers reduce postage costs and come with a clear 'Do Not Bend' warning to ensure safe delivery. Perfect for professionals who demand durability and sustainability in their office supplies.

## Description

Great prices on your favourite Office brands plus free delivery and returns on eligible orders.

Review: Good Quality - Good quality & value. Adhesive sticks well. Board is sufficiently rigid to offer protection to items.
Review: Good and strong - Good strong bags Good price

## Features

- A MAILING ESSENTIAL: Pack of 10 x C3 rigid mailers designed to contain unfolded A3 paper (or A2 paper folded in half) - perfectly sized for posting & storing flat posters, artwork, sketches, paintings, blueprints, calendars & legal documents
- WILL NOT BEND: 120gsm kraft paper front & 1000 micron board back construction offers all-round protection & rigidity to keep contents flat, crease-free & safe. "Please do not bend" is printed in large red font on the front to caution all handlers.
- QUICK, EASY & SECURE: Built-in peel & seal strip reduces packing time & cost by providing a strong & hassle-free seal while also offering extended shelf-life over self seal envelopes - just remove the strip & press the flap down to seal!
- SAVE ON PACKAGING & POSTAGE: A more cost-effective & waste-free alternative to all board envelopes, these light yet sturdy card backed envelopes are also cheaper to post. You may write on them directly to eliminate the need for extra address labels.
- AN ECO-CONSCIOUS CHOICE: Made from 100% recycled material, fully kerbside recyclable & biodegradable - these hard back envelopes are a plastic-free, sustainable & environmentally conscious packaging choice for office, school & home use.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B01H01UHSG |
| Best Sellers Rank | 882 in Business, Industry & Science ( See Top 100 in Business, Industry & Science ) 7 in Packing List Envelopes |
| Brand | Triplast |
| Brand Name | Triplast |
| Closure Type | Self-Seal |
| Closure type | Self-Seal |
| Colour | Brown |
| Country Of Origin | United Kingdom |
| Customer Reviews | 4.6 out of 5 stars 942 Reviews |
| Global Trade Identification Number | 05056025163140 |
| Item Dimensions L x W | 45.7L x 32.4W centimetres |
| Item Shape | Rectangular |
| Item Type Name | Board Backed Envelopes |
| Item Weight | 114 g |
| Item height | 0.2 centimetres |
| Manufacturer | Triplast |
| Material | Paper |
| Material Type | Paper |
| Model Name | Board Back Envelopes |
| Number of Items | 10 |
| Number of items | 10 |
| Occasion | Anytime |
| Occasion Type | Anytime |
| Product Warranty | China |
| Recommended Uses For Product | Cash, Disc, Invitation Card, Letter |
| Size | A3 C3 (457 x 324mm) |
| Special Features | Lightweight, Self-Adhesive Closure |
| Style | Flat |
| Unit Count | 10.0 count |

## Product Details

- **Brand:** Triplast
- **Closure type:** Self-Seal
- **Colour:** Brown
- **Material:** Paper
- **Occasion:** Anytime

## Images

![Triplast 10 x A3 C3 Manilla Hard Board Back Envelopes (457x324mm) - Cardboard Backed Mailers with Peel & Seal Strip - Rigid Do Not Bend Envelopes for Mailing Posting Shipping & Storing Documents - Image 1](https://m.media-amazon.com/images/I/61KEjAvFn0L.jpg)
![Triplast 10 x A3 C3 Manilla Hard Board Back Envelopes (457x324mm) - Cardboard Backed Mailers with Peel & Seal Strip - Rigid Do Not Bend Envelopes for Mailing Posting Shipping & Storing Documents - Image 2](https://m.media-amazon.com/images/I/71EPCxBtg0L.jpg)
![Triplast 10 x A3 C3 Manilla Hard Board Back Envelopes (457x324mm) - Cardboard Backed Mailers with Peel & Seal Strip - Rigid Do Not Bend Envelopes for Mailing Posting Shipping & Storing Documents - Image 3](https://m.media-amazon.com/images/I/71NaFQ8VaqL.jpg)
![Triplast 10 x A3 C3 Manilla Hard Board Back Envelopes (457x324mm) - Cardboard Backed Mailers with Peel & Seal Strip - Rigid Do Not Bend Envelopes for Mailing Posting Shipping & Storing Documents - Image 4](https://m.media-amazon.com/images/I/71XQNFaZ38L.jpg)
![Triplast 10 x A3 C3 Manilla Hard Board Back Envelopes (457x324mm) - Cardboard Backed Mailers with Peel & Seal Strip - Rigid Do Not Bend Envelopes for Mailing Posting Shipping & Storing Documents - Image 5](https://m.media-amazon.com/images/I/81OOPE9wx2L.jpg)

## Available Options

This product comes in different **Number Of Items** options.

## Questions & Answers

**Q: I want to send a lightweight picture frame 30X40cm would these work thank you**
A: Probably but you will need to use plenty bubble wrap on the picture frame to prevent damage. This is an envelope with a hard back and offered no padding or protection against the item you are sending.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Good Quality
*by L***N on 18 April 2025*

Good quality & value. Adhesive sticks well. Board is sufficiently rigid to offer protection to items.

### ⭐⭐⭐⭐⭐ Good and strong
*by M***T on 13 September 2024*

Good strong bags Good price

### ⭐⭐⭐⭐⭐ Just the job for posting art prints
*by R***R on 13 August 2025*

Just the job for posting art prints.

## Frequently Bought Together

- Triplast 457 x 324 mm A3 C3 Manilla Hard Board Backed Envelopes (Pack of 10), Brown
- Amazon Basics Multipurpose Copy Printer Paper, 8.5 x 11 in, 20 lb, 10 Reams, 5000 Sheets, 92 Bright, White
- Amazon Basics 10" x 13" Gummed Seal Clasp Kraft Mailing Envelopes, 100-Pack, brown

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**Shop now:** [https://www.desertcart.hk/products/51250158-triplast-10-x-a3-c3-manilla-hard-board-back-envelopes](https://www.desertcart.hk/products/51250158-triplast-10-x-a3-c3-manilla-hard-board-back-envelopes)

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*Product available on Desertcart Hong Kong*
*Store origin: HK*
*Last updated: 2026-02-04*