---
product_id: 50590449
title: "Twin Pack Kidde Firex KF20 Mains Powered Optical Smoke Alarm with 9V Back Up Batteries | KF2 | 4973"
brand: "kidde"
price: "€ 77.51"
currency: EUR
in_stock: true
reviews_count: 11
category: "Kidde"
url: https://www.desertcart.it/products/50590449-twin-pack-kidde-firex-kf20-mains-powered-optical-smoke-alarm
store_origin: IT
region: Italy
---

# Mains-powered with low energy use 9V battery backup included Interlink up to 23 alarms Twin Pack Kidde Firex KF20 Mains Powered Optical Smoke Alarm with 9V Back Up Batteries | KF2 | 4973

**Brand:** kidde
**Price:** € 77.51
**Availability:** ✅ In Stock

## Summary

> 🔥 Stay ahead of danger with Kidde’s smart, interconnected smoke defense! 🔗

## Quick Answers

- **What is this?** Twin Pack Kidde Firex KF20 Mains Powered Optical Smoke Alarm with 9V Back Up Batteries | KF2 | 4973 by kidde
- **How much does it cost?** € 77.51 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.it](https://www.desertcart.it/products/50590449-twin-pack-kidde-firex-kf20-mains-powered-optical-smoke-alarm)

## Best For

- kidde enthusiasts

## Why This Product

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

## Key Features

- • **Tamper-Proof Design:** Locking device prevents unauthorized removal, ensuring peace of mind
- • **Smart Nuisance Control:** Dust compensation and bug screen reduce false alarms
- • **Seamless Safety Network:** Interlink up to 23 Kidde alarms for whole-home protection
- • **User-Friendly Operation:** Combined Test/Hush™ button for easy testing and temporary silencing
- • **Reliable Power Assurance:** Mains-powered with 9V alkaline backup for uninterrupted security

## Overview

The Kidde Firex KF20 is a mains-powered optical smoke alarm featuring a 9V battery backup, capable of interlinking with up to 23 other Kidde alarms for synchronized alerts. Designed for reliable detection of slow, smouldering fires, it includes advanced dust and bug filters to minimize false alarms, a combined test/hush button for easy maintenance, and a tamper-resistant lock for enhanced security. Certified to UK safety standards with a 6-year warranty, it’s the smart choice for comprehensive home fire safety.

## Description

Mains-powered optical smoke alarm that can be interlinked with up to 23 other Kidde mains alarms, be they ionisation, optical or heat. Once interlinked, the detection of the relevant danger by an individual unit will sound across all the connected alarms. Optical alarms are for use in escape or circulation routes and in areas where there is a danger of ignition of furniture and surroundings by cigarettes producing slow, smouldering fires. This mains-powered unit should be installed by a qualified electrician and can be used throughout the home, except in the kitchen where a Firex Heat Alarm is recommended. These alarms comply with UK Building Regulations for new housing and associated standards (Grade D BS 5839, Part 6).

Review: Easy to install. Good detector - Great pair of smoke optical smoke detectors. Easy to fit as as always quick delivery from desertcart. Recommended.
Review: REPLACES THE KF10 - Perfect replacement for my firex KF10. Didn't need to change ANYTHING. Just plugged the existing wires in. Push and click onto existing ceiling plate. Job done.!

## Features

- Mains-powered optical smoke alarm that can be interlinked with up to 23 other Kidde mains alarms, be they ionisation, optical or heat. Once interlinked, the detection of the relevant danger by an individual unit will sound across all the connected alarms.
- Interlink with up to 23 Kidde Firex hard-wired alarms – all alarms sound if danger is detected
- Mains operation – 9V Alkaline back-up battery supplied as standard
- Reduced energy consumption – lower lifetime running costs (* compared to previous Firex alarms)
- Combined Test/HushTM button allows regular testing of alarm function and can be used to temporarily silence nuisance alarms
- Dust compensation and bug screen – reduces nuisance alarms
- Alarm memory – identifies source unit within interconnecting network
- Auto reset after activation
- Tamper-resistant locking device prevents unauthorised removal without the use of a tool
- Warranty 6 years, BSI certified to BS EN14604:2005 and CE tested and certified to 0086-CPD-535595 15 EN14604:2005

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00LGX1TSC |
| Alarm | Audible |
| Best Sellers Rank | 2,925 in DIY & Tools ( See Top 100 in DIY & Tools ) 19 in Smoke Alarms |
| Brand | Kidde |
| Colour | White |
| Country of Origin | China |
| Customer Reviews | 4.6 4.6 out of 5 stars (902) |
| Item Weight | 500 Grams |
| Model Number | KF2 4973 |
| Power source | Battery Powered |
| Product Style | Classic |
| Sensor Type | Photoelectric |
| UPC | 799441946892 |

## Product Details

- **Alarm:** Audible
- **Brand:** Kidde
- **Colour:** White
- **Item weight:** 500 Grams
- **Power source:** Battery Powered
- **Sensor type:** Photoelectric
- **Style:** Classic
- **UPC:** 799441946892

## Images

![Twin Pack Kidde Firex KF20 Mains Powered Optical Smoke Alarm with 9V Back Up Batteries | KF2 | 4973 - Image 1](https://m.media-amazon.com/images/I/31Xv-Q7FuUL.jpg)

## Questions & Answers

**Q: Will this alarm fit on to existing backing plate of a firex 1240c series alarm?**
A: I bought my Kidde alarms to replace existing alarms from a different manufacturer and new backing plates were supplied. However I realised that there was little difference between the backing plates so I just used the ones that were already there.  Given you are talking about a firex alarm, I'm sure you'd be ok but you might like to check the manufacturer's website to check.

**Q: Are you selling 2 x kf2 or 2 x kf20 ?**
A: The KF2 is discontinued and the newer version is the KF20. You will receive 2x KF20 alarms.

**Q: Are these same fittings for firex padc240 ?**
A: Yes they will replace the old Firex model

**Q: My alarms are slightly different but need replacing but my wires are different colours mine are blue white and brown is this a problem?**
A: All alarms now have a "Link" wire, they are used to couple up (or link) numbers of alarms together, so if one alarm sounds, all sound. That is what the white wire is used for. If you don't need or want to link alarms, just make safe the white wire with a connector and leave it disconnected. The brown is the permanent live, the Blue is the neutral, both have to be supplied from your mains electric circuit.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Easy to install. Good detector
*by M***T on 30 January 2026*

Great pair of smoke optical smoke detectors. Easy to fit as as always quick delivery from amazon. Recommended.

### ⭐⭐⭐⭐⭐ REPLACES THE KF10
*by M***N on 19 February 2026*

Perfect replacement for my firex KF10. Didn't need to change ANYTHING. Just plugged the existing wires in. Push and click onto existing ceiling plate. Job done.!

### ⭐⭐⭐⭐⭐ Easy installation
*by M***R on 22 February 2026*

Next day delivery, easy to install, great product.

## Frequently Bought Together

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- Firex KF30 Kidde Firex Alarm, White

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*Product available on Desertcart Italy*
*Store origin: IT*
*Last updated: 2026-05-09*