---
product_id: 504446575
title: "4\" Inch / 100 mm Duct Backdraft Blockers - Pipe Connector with Backdraught Shutter - Backflow Preventer - Dryer Vent Adapter - Inline Air Extractor - Pipe Line Coupler with Valve"
brand: "repa market"
price: "€ 24.89"
currency: EUR
in_stock: true
reviews_count: 8
category: "Repa Market"
url: https://www.desertcart.de/products/504446575-4-inch-100-mm-duct-backdraft-blockers-pipe-connector-backdraught
store_origin: DE
region: Germany
---

# Advanced backflow damper 3.89 inch insertion diameter DIY-friendly easy installation 4" Inch / 100 mm Duct Backdraft Blockers - Pipe Connector with Backdraught Shutter - Backflow Preventer - Dryer Vent Adapter - Inline Air Extractor - Pipe Line Coupler with Valve

**Brand:** repa market
**Price:** € 24.89
**Availability:** ✅ In Stock

## Summary

> 💨 Seal the breeze, own the comfort — ventilation perfected!

## Quick Answers

- **What is this?** 4" Inch / 100 mm Duct Backdraft Blockers - Pipe Connector with Backdraught Shutter - Backflow Preventer - Dryer Vent Adapter - Inline Air Extractor - Pipe Line Coupler with Valve by repa market
- **How much does it cost?** € 24.89 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.de](https://www.desertcart.de/products/504446575-4-inch-100-mm-duct-backdraft-blockers-pipe-connector-backdraught)

## Best For

- repa market enthusiasts

## Why This Product

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

## Key Features

- • **Effortless DIY Installation:** No professional needed—get your ventilation system upgraded in minutes.
- • **Superior Backflow Prevention:** Balanced damper blocks cold drafts, odors, and noise for a fresher indoor environment.
- • **Versatile Multi-Duct Compatibility:** Optimized for complex ductwork, HVAC, and dryer vent systems to maintain airflow integrity.
- • **Precision Fit for Seamless Integration:** Exact 3.89 inch diameter ensures perfect duct compatibility without leaks.
- • **Durable Build for Long-Term Performance:** Robust male spigot and plastic housing designed to withstand daily wear and tear.

## Overview

The Repa Market 4" Duct Backdraft Blocker is a precision-engineered pipe connector featuring a 3.89 inch insertion diameter and a balanced damper to prevent backflow of air, odors, and noise. Designed for easy DIY installation, it fits seamlessly into multi-section ducting systems including HVAC, dryer vents, and inline extractors. Constructed with durable plastic and a male spigot, it ensures long-lasting ventilation efficiency and comfort in your home or workspace.

## Description

Free delivery and returns on all eligible orders. Shop Repa Market 4" Inch / 100 mm Duct Backdraft Blockers - Pipe Connector with Backdraught Shutter - Backflow Preventer - Dryer Vent Adapter - Inline Air Extractor - Pipe Line Coupler with Valve.

Review: Stops the cold breeze - Simple idea but works very well. Stops the breeze comming through the ducting even on the windy days we've had
Review: Just what I needed - Mice simple device, installed and doing the job, star lost due to slower delivery time than promised...

## Features

- PRECISE DIMENSIONS: Insertion diameter: 3.89 inch / 99 mm Insertion depth: 1.18 inch / 30 mm Total width: 2.4 inch / 62 mm., this product offers easy do-it-yourself installation, ensuring hassle-free compatibility with your ventilation system.
- EFFICIENT VENTILATION: Engineered for reliable airflow control in bathrooms, kitchens, cooker hoods, and inline extraction setups — helps prevent cold drafts, odors, and outside air from entering through your dryer vent or duct system.
- ADVANCED BACKFLOW PROTECTION: Equipped with a pre-installed balanced damper that effectively stops unwanted odors, noises, and drafts from backflowing through your duct system.
- OPTIMIZED FOR MULTI-SECTION DUCTING: A critical airflow safeguard for long or multi-section ductwork, ensuring stable performance in ventilation, passive stack venting, air conditioning, positive-pressure systems, tumble dryer setups, HVAC installations, and air heating networks.
- DURABLE MALE-SPIGOT DESIGN: Constructed with a male spigot and durable white plastic housing, ensuring long-lasting performance in extractor fan systems.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B084BP47PT |
| Best Sellers Rank | 32,925 in DIY & Tools ( See Top 100 in DIY & Tools ) 90 in Ducting |
| Brand | Repa Market |
| Colour | White |
| Connector Type | Coupling |
| Connector type | Coupling |
| Country of Origin | Latvia |
| Customer Reviews | 4.1 out of 5 stars 366 Reviews |
| Included Components | Male Fit Connector with Suhutter |
| Item Dimensions | 10 x 10 x 6.2 centimetres |
| Item dimensions L x W x H | 10 x 10 x 6.2 centimetres |
| Manufacturer | Repa Market |
| Material | Plastic |
| Number of Pieces | 1 |
| Size | 100mm |
| Thread Type | BSP |
| Unit Count | 1.0 count |

## Product Details

- **Brand:** Repa Market
- **Colour:** White
- **Connector type:** Coupling
- **Item dimensions L x W x H:** 10 x 10 x 6.2 centimetres
- **Manufacturer:** Repa Market
- **Material:** Plastic
- **Number of pieces:** 1
- **Size:** 100mm
- **Thread type:** BSP

## Images

![4" Inch / 100 mm Duct Backdraft Blockers - Pipe Connector with Backdraught Shutter - Backflow Preventer - Dryer Vent Adapter - Inline Air Extractor - Pipe Line Coupler with Valve - Image 1](https://m.media-amazon.com/images/I/51PWHxsW3ZL.jpg)

## Questions & Answers

**Q: Will drafts from outside open the flap?**
A: It is designed so that when installed correctly, the flap/door will be in a closed position and only able to be opened from one direction. So, to answer the question, no outside pressue will not open the flap (as long as it is installed correctly).

**Q: How tall is it?**
A: 4”

**Q: Is this to be installed on a vertical or horizontal run or both?**
A: Horizontal. It's own weight keeps it closed.

**Q: Can I use this to replace the cap where the dryer vent comes out of the house? Does it fit in the hole?**
A: It is just a gravity actuated valve like devise and is not designed for an exterior application. Rain, insects and rodents would be able to enter the dwelling through that simple valve.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Stops the cold breeze
*by M***N on 11 February 2024*

Simple idea but works very well. Stops the breeze comming through the ducting even on the windy days we've had

### ⭐⭐⭐⭐ Just what I needed
*by A***R on 16 October 2023*

Mice simple device, installed and doing the job, star lost due to slower delivery time than promised...

### ⭐⭐⭐⭐⭐ Good quality
*by A***R on 12 December 2025*

Excellent quality fast delivery

## Frequently Bought Together

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**Shop now:** [https://www.desertcart.de/products/504446575-4-inch-100-mm-duct-backdraft-blockers-pipe-connector-backdraught](https://www.desertcart.de/products/504446575-4-inch-100-mm-duct-backdraft-blockers-pipe-connector-backdraught)

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*Product available on Desertcart Germany*
*Store origin: DE*
*Last updated: 2026-03-02*