---
product_id: 63444412
title: "Triplast 20 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: "฿4426"
currency: THB
in_stock: true
reviews_count: 13
category: "Triplast"
url: https://www.desertcart.co.th/products/63444412-triplast-20-x-a3-c3-manilla-hard-board-back-envelopes
store_origin: TH
region: Thailand
---

# 457x324mm perfect A3 fit Peel & seal strip for secure closure 1000 micron rigid board backing Triplast 20 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:** ฿4426
**Availability:** ✅ In Stock

## Summary

> 📦 Mail like a pro, protect like a boss!

## Quick Answers

- **What is this?** Triplast 20 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?** ฿4426 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.th](https://www.desertcart.co.th/products/63444412-triplast-20-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 Shipping:** Lightweight yet sturdy design reduces postage costs without compromising protection.
- • **Seal the Deal in Seconds:** Built-in peel & seal strip slashes packing time with a strong, hassle-free closure.
- • **Bold 'Do Not Bend' Warning:** Large red print ensures your important documents get the VIP treatment they deserve.
- • **Flat & Fabulous Protection:** 120gsm kraft front + 1000 micron board back keeps your documents crease-free and pristine.

## Overview

Triplast’s 20-pack of A3 C3 manilla hard board envelopes combines rigid 1000 micron backing with a 120gsm kraft front to protect flat documents, posters, and artwork. Featuring a peel & seal strip for quick, secure closure, these eco-friendly, lightweight mailers reduce postage costs while ensuring your contents arrive crease-free. Perfect for professionals who demand durability, sustainability, and efficiency in their mailing 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 20 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 | B01H01UHS6 |
| Best Sellers Rank | 4,610 in Business, Industry & Science ( See Top 100 in Business, Industry & Science ) 24 in Packing List Envelopes |
| Brand | Triplast |
| Closure | Self-Seal |
| Colour | Brown |
| Customer Reviews | 4.6 4.6 out of 5 stars (942) |
| Date First Available | 13 Jun. 2016 |
| Item Weight | 114 g |
| Manufacturer | Triplast |
| Manufacturer Part Number | A3 C3 |
| Material Type | Paper |
| Model Number | A3 C3 |
| Number of Items | 20 |
| Paper Finish | Uncoated |
| Product Dimensions | 32.4 x 45.7 x 0.2 cm; 113.85 g |
| Shape | Rectangular |
| Sheet Size | A3 |
| Size | A3 C3 (457 x 324mm) |

## Product Details

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

## Images

![Triplast 20 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/71EPCxBtg0L.jpg)
![Triplast 20 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/71NaFQ8VaqL.jpg)
![Triplast 20 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/71XQNFaZ38L.jpg)
![Triplast 20 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/81dlZ5mE+tL.jpg)
![Triplast 20 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/61KEjAvFn0L.jpg)

## Available Options

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

## 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 20 x A3 C3 Manilla Hard Board Back Envelopes (457x324mm) - Cardboard Backed Envelopes with Peel & Seal Strip - Rigid Do Not Bend Envelopes for Mailing Posting Shipping & Storing Documents
- 20Pcs A4 Envelopes Self-Seal iSOUL 324mm x 229mm A4 C4 Manilla Hard Board Backed Envelopes Do Not Bend Envelope

---

## Why Shop on Desertcart?

- 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016
- 🌍 **Shop Globally** — Access 737+ million products across 21 categories
- 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price
- 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members)
- 🔒 **Secure Payments** — Trusted payment options with buyer protection
- ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews

**Shop now:** [https://www.desertcart.co.th/products/63444412-triplast-20-x-a3-c3-manilla-hard-board-back-envelopes](https://www.desertcart.co.th/products/63444412-triplast-20-x-a3-c3-manilla-hard-board-back-envelopes)

---

*Product available on Desertcart Thailand*
*Store origin: TH*
*Last updated: 2026-02-22*