---
product_id: 60377604
title: "Purely Packaging C3 (A3) 450 x 324 mm Board Back Pocket Peel & Seal Envelopes (4200/50) Manilla - Pack of 50"
brand: "blake"
price: "HK$768"
currency: HKD
in_stock: true
reviews_count: 13
category: "Blake"
url: https://www.desertcart.hk/products/60377604-purely-packaging-c3-a3-450-x-324-mm-board-back
store_origin: HK
region: Hong Kong
---

# C3 size 450x324 mm Strong peel & seal closure Heavy-duty board back protection Purely Packaging C3 (A3) 450 x 324 mm Board Back Pocket Peel & Seal Envelopes (4200/50) Manilla - Pack of 50

**Brand:** blake
**Price:** HK$768
**Availability:** ✅ In Stock

## Summary

> 📬 Elevate your mail game — protect, seal, and impress every time!

## Quick Answers

- **What is this?** Purely Packaging C3 (A3) 450 x 324 mm Board Back Pocket Peel & Seal Envelopes (4200/50) Manilla - Pack of 50 by blake
- **How much does it cost?** HK$768 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/60377604-purely-packaging-c3-a3-450-x-324-mm-board-back)

## Best For

- blake enthusiasts

## Why This Product

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

## Key Features

- • **Eco-Conscious Choice:** Crafted from 100% recycled materials, combining sustainability with premium quality.
- • **Effortless Security Seal:** Strong peel & seal closure ensures your contents stay safe and tamper-proof with zero hassle.
- • **Clear 'Do Not Bend' Warning:** Printed prominently on the front to reduce mishandling and guarantee professional presentation.
- • **Ultimate Flat Mail Protection:** Heavy-duty board backing shields certificates, prints, and photos from bending or damage.
- • **Perfect for Professional Correspondence:** Ideal for sending important documents, large letters, and cards with confidence and style.

## Overview

Blake Purely Packaging C3 Board Back Peel & Seal Envelopes (Pack of 50) offer robust protection for flat mail items with their heavy-duty board backing and secure peel & seal closure. Sized at 450 x 324 mm, these manilla envelopes feature a clear 'Please do not bend' print to ensure careful handling. Made from 100% recycled materials, they combine durability, eco-friendliness, and professional presentation, making them a top choice for safeguarding certificates, photographs, and important documents.

## Description

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

Review: The only brand of board backed envelopes I will buy - Excellent board backed envelopes, with 'please do not bend' printed clearly on them. I made the mistake recently of buying a cheaper alternative and definitely regret it. (For the saving of several pounds, I am now stuck with more than 100 flimsy, bendable envelopes with an unpleasant font on the front!) Both the grey board and the brown kraft paper used are of decent thickness to protect most flat items. They are also durable and reliable. Would definitely recommend. Although, for e.g. single prints, they might still need cardboard stiffeners so bear this in mind.
Review: Great product - Very durable, functions well. Seals very well. Postage is protected. Great value for money. Brought many times. Light brown colour. Can be used for cards and large letter. Lightweight

## Features

- Make a difference to your mail with these Purely Packaging Board Back envelopes by Blake
- Heavy Duty Board Back to protect certificates, photographs, prints and more
- Strong Peel & Seal closure for ease of use, additional security and longer shelf life
- Printed 'Please do not bend' on the face for extra safety
- Printed Do Not Bend on the front

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00O4X7W00 |
| Best Sellers Rank | 5,706 in Stationery & Office Supplies ( See Top 100 in Stationery & Office Supplies ) 93 in Envelopes |
| Brand | Blake |
| Closure | Self-Seal |
| Colour | Manilla |
| Customer Reviews | 4.6 4.6 out of 5 stars (2,279) |
| Date First Available | 23 Sept. 2014 |
| Item Weight | 2.49 kg |
| Manufacturer | Blake Envelopes |
| Manufacturer Part Number | 4200/50 |
| Material Type | Cardboard, Cardstock, Paper |
| Model Number | 4200/50 |
| Number of Items | 50 |
| Paper Finish | Uncoated |
| Product Dimensions | 46 x 33.5 x 10.5 cm; 2.49 kg |
| Shape | Rectangular |
| Sheet Size | C3 |
| Size | C3 450 x 324 mm |
| Total Recycled Content | 100 |

## Product Details

- **Brand:** Blake
- **Closure type:** Self-Seal
- **Colour:** Manilla
- **Material:** Cardboard, Cardstock, Paper
- **Occasion:** Envelopes

## Images

![Purely Packaging C3 (A3) 450 x 324 mm Board Back Pocket Peel & Seal Envelopes (4200/50) Manilla - Pack of 50 - Image 1](https://m.media-amazon.com/images/I/81S2chsbi1L.jpg)

## Available Options

This product comes in different **Color, Size, Style** options.

## Questions & Answers

**Q: which size is a4? c4?**
A: The 'A' prefix is the paper size; the 'C' prefix is the envelope size. A4 paper fits unfolded inside a C4 envelope (similarly A5/C5, A6/C6, etc).

**Q: What is the gsm of both the paper and the board? Want a thick board back that won’t easily bend**
A: I don't know what the gsm is but I found them pretty sturdy and sent photos using them.

**Q: would my card 160cm x 155cm fit in this envelope**
A: Yes the envelopes are 229 x 162 so your items would fit.

**Q: Will this fit a A3 print?**
A: Yes.  I use it to fit A3 booklets.

## Customer Reviews

### ⭐⭐⭐⭐⭐ The only brand of board backed envelopes I will buy
*by T***R on 6 December 2024*

Excellent board backed envelopes, with 'please do not bend' printed clearly on them. I made the mistake recently of buying a cheaper alternative and definitely regret it. (For the saving of several pounds, I am now stuck with more than 100 flimsy, bendable envelopes with an unpleasant font on the front!) Both the grey board and the brown kraft paper used are of decent thickness to protect most flat items. They are also durable and reliable. Would definitely recommend. Although, for e.g. single prints, they might still need cardboard stiffeners so bear this in mind.

### ⭐⭐⭐⭐⭐ Great product
*by V***. on 30 December 2024*

Very durable, functions well. Seals very well. Postage is protected. Great value for money. Brought many times. Light brown colour. Can be used for cards and large letter. Lightweight

### ⭐⭐⭐⭐⭐ Quick delivery
*by P***Y on 2 December 2025*

Quick delivery at a good price

## Frequently Bought Together

- Blake Purely Packaging C3 (A3) 450 x 324 mm Board Back Pocket Peel & Seal Envelopes (4200/50) Manilla - Pack of 50
- A3 Cello Bags - Crystal Clear & Good Thickness - for A3 Artwork/Photos (420MM x 306MM) - Makes Your Work Feel Pricey - 30mm Seal - 40Micron - Super Strong Seams
- House of Card & Paper Grey Kraft Board 1500micron 945gsm A3 Size 30 Sheets per Pack, HCP476

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*Product available on Desertcart Hong Kong*
*Store origin: HK*
*Last updated: 2026-02-19*