---
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: "£35.88"
currency: GBP
in_stock: true
category: "Blake"
url: https://www.desertcart.co.uk/products/60377604-purely-packaging-c3-a3-450-x-324-mm-board-back
store_origin: GB
region: United Kingdom
---

# 450 x 324 mm C3 size 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:** £35.88
**Availability:** ✅ In Stock

## Summary

> 📬 Seal your success with style and security!

## 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?** £35.88 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.uk](https://www.desertcart.co.uk/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

- • **Clear 'Do Not Bend' Warning:** Printed front message adds an extra layer of care during transit, reducing risk of damage.
- • **Generous C3 Size for Versatility:** Spacious 450 x 324 mm dimensions accommodate large documents, cards, and artwork with ease.
- • **Ultimate Protection for Your Mail:** Heavy-duty board back shields certificates, photos, and prints from bending or damage.
- • **Eco-Friendly & Professional Manilla:** Classic manilla color offers a premium, lightweight, and sustainable mailing solution.
- • **Effortless Security with Peel & Seal:** Strong self-adhesive closure ensures tamper-proof sealing and quick, mess-free use.

## Overview

Blake Purely Packaging C3 Board Back Envelopes (450 x 324 mm) combine robust cardboard backing with a strong peel & seal closure, ensuring your important documents and prints arrive pristine. With a clear 'Please do not bend' warning and a professional manilla finish, these envelopes offer reliable protection and effortless mailing for business and creative needs. Pack of 50, trusted by thousands for durability and value.

## Description

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

## 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 | 16,512 in Stationery & Office Supplies ( See Top 100 in Stationery & Office Supplies ) 174 in Envelopes |
| Brand Name | Blake |
| Closure Type | Self-Seal |
| Colour | Manilla |
| Customer Reviews | 4.6 4.6 out of 5 stars (2,308) |
| Global Trade Identification Number | 05055559753087, 05055559719472 |
| Item Dimensions L x W | 45L x 32.4W centimetres |
| Item Shape | Rectangular |
| Item Type Name | Purely Packaging C3 450x324mm Board Back Envelope Box of 50 |
| Item Weight | 2.49 kg |
| Manufacturer | Blake Envelopes |
| Material Type | Cardstock, Paper, Cardboard |
| Model Name | Everyday - Board Back Envelopes |
| Number of Items | 50 |
| Occasion | Envelopes |
| Occasion Type | Office, Envelopes, Arts and Craft, Mailing, Business |
| Recommended Uses For Product | Office, Letter, Envelopes, Invitation Card, Business |
| Size | C3 450 x 324 mm |
| Special Features | Board, Self-Adhesive Closure, Lightweight, Premium, Card |
| Style | Pack of 50 (No Window) |
| Unit Count | 50.0 count |

## Product Details

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

## 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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**Shop now:** [https://www.desertcart.co.uk/products/60377604-purely-packaging-c3-a3-450-x-324-mm-board-back](https://www.desertcart.co.uk/products/60377604-purely-packaging-c3-a3-450-x-324-mm-board-back)

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*Product available on Desertcart United Kingdom*
*Store origin: GB*
*Last updated: 2026-09-02*