Kidde KF21 Sentry Mains Powered Optical Smoke Alarm with 9V Alkaline Battery Back-Up c/w Quick Fit Base
Kidde KF21 Sentry Mains Powered Optical Smoke Alarm with 9V Alkaline Battery Back-Up c/w Quick Fit Base
Overall Rating: 4.2 / 5 (average from multiple review sources, as of 17 Oct 2026)
Based on a total of 4,635 customer reviews from independent review platforms.
Sources & Transparency:
The values are derived from publicly available retailer ratings from platforms such as Feefo, http://Reviews.io , Trustpilot, and others, and are aggregated monthly.
All brand names and logos are the property of their respective owners.
Notice:
pricehunter.co.uk cannot guarantee that published shop ratings originate from consumers who have actually made a purchase from the reviewed retailer.
Based on a total of 4,635 customer reviews from independent review platforms.
Sources & Transparency:
The values are derived from publicly available retailer ratings from platforms such as Feefo, http://Reviews.io , Trustpilot, and others, and are aggregated monthly.
All brand names and logos are the property of their respective owners.
Notice:
pricehunter.co.uk cannot guarantee that published shop ratings originate from consumers who have actually made a purchase from the reviewed retailer.
Cheapest Total Price
2-3 Days
Direct debit
Direct debit
PayPal
PayPal
Payment in advance
Payment in advance
Mastercard
Mastercard
Visa
Visa
Google Checkout
Google Checkout
Payment by invoice
Payment by invoice
£21.38
Free Delivery
Kidde Firex Sentry KF21 Mains Powered Smoke Alarm - Optical Smoke Detector with Backup Battery - Wired, Interlinked Smoke Alarms for Home with Test Button and LED Indicators - White
Overall Rating: 1.5 / 5 (average from multiple review sources, as of 3 Oct 2026)
Based on a total of 70 customer reviews from independent review platforms.
Sources & Transparency:
The values are derived from publicly available retailer ratings from platforms such as Feefo, http://Reviews.io , Trustpilot, and others, and are aggregated monthly.
All brand names and logos are the property of their respective owners.
Notice:
pricehunter.co.uk cannot guarantee that published shop ratings originate from consumers who have actually made a purchase from the reviewed retailer.
Based on a total of 70 customer reviews from independent review platforms.
Sources & Transparency:
The values are derived from publicly available retailer ratings from platforms such as Feefo, http://Reviews.io , Trustpilot, and others, and are aggregated monthly.
All brand names and logos are the property of their respective owners.
Notice:
pricehunter.co.uk cannot guarantee that published shop ratings originate from consumers who have actually made a purchase from the reviewed retailer.
In stock
Direct debit
Direct debit
Mastercard
Mastercard
Visa
Visa
£22.99
Free Delivery
Cheapest offer
Kidde KF21 Sentry Mains Powered Optical Smoke Alarm with 9V Battery Back-Up The Kidde KF21 Sentry Optical Smoke Alarm is a reliable mains-powered smoke detector designed to provide early warning of slow, smouldering fires within residential properties. Featuring an advanced optical sensor, the KF21 is ideal for hallways, landings, bedrooms, living areas and loft spaces, helping to improve fire safety throughout the home. This interconnectable smoke alarm can be linked with up to 23 compatible Kidde FIREX smoke, heat and carbon monoxide alarms, ensuring that when one alarm detects danger, all connected alarms sound simultaneously for maximum protection. Designed with installers in mind, the KF21 includes a Quick-Fit Slide-On Base for fast and tidy installation, while the 150mm flared base plate neatly covers marks left by larger existing alarms during retrofit projects. Key Features Mains-powered optical smoke alarm with 9V alkaline battery back-up Interconnects with up to 23 compatible
£21.38
2-3 Days
westbasedirect.com
🤖 Ask ChatGPT
💡 Is it worth the price?
🔁 Better alternatives?
⭐ What do users say?
Kidde KF21 Sentry Mains Powered Optical Smoke Alarm with 9V Alkaline Battery Back-Up c/w Quick Fit Base - Details
▶ Finding you the best price!
We have found 2 prices for Kidde KF21 Sentry Mains Powered Optical Smoke Alarm with 9V Alkaline Battery Back-Up c/w Quick Fit Base. Our price list is completely transparent with the cheapest listed first. Additional delivery costs may apply.
Kidde KF21 Sentry Mains Powered Optical Smoke Alarm with 9V Alkaline Battery Back-Up c/w Quick Fit Base - Price Information
- Cheapest price: £21.38
- The cheapest price is offered by westbasedirect.com. You can order the product there.
- The price range for the product Kidde KF21 Sentry Mains Powered Optical Smoke Alarm with 9V Alkaline Battery Back-Up c/w Quick Fit Base is €£21.38to €£22.99 with a total of 2 offers.
- Payment methods: The online shop westbasedirect.com supports: Direct debit, PayPal, Payment in advance, Mastercard, Visa, Google Checkout, Payment by invoice
- Delivery: The shortest delivery time is 2-3 Days working days offered by westbasedirect.com.
Similar products
Kidde Sentry KF21 Hard Wired Mains Interconnectable Optical Fire Smoke Alarm
£24.89
GBP 24.89 / Unit
ebay.co.uk
Free Delivery
Kidde Sentry KF21 Hard Wired Mains Interconnectable Optical Fire Smoke Alarm
£24.80
GBP 24.80 / Unit
ebay.co.uk
Free Delivery
Kidde KF21R Sentry Mains Powered Optical Smoke Alarm with Sealed-In Rechargeable Lithium Battery Back-Up c/w Quick Fit Base
£49.33
westbasedirect.com
Free Delivery
Kidde Sentry 1x KF21 Optical Smoke & 1x KF31 Heat Alarm Kit Mains Powered with 9V Alkaline Battery Back-Up c/w Quick Fit Base
£58.56
westbasedirect.com
Free Delivery
Kidde Sentry 5x KF21R Optical Smoke & 1x KF31R Heat Alarm Kit Mains Powered with Sealed-In Rechargeable Battery Back-Up c/w Quick Fit Base
£300.20
westbasedirect.com
Free Delivery
Don't forget your voucher code:
Report Illegal Concerns
You are about to report a violation based on the EU Digital Services Act (DSA).