SKU: 71848446569

Kidde Sentry 4x KF21R Optical Smoke & 1x KF31R Heat Alarm Kit Mains Powered with Sealed-In Rechargeable Battery Back-Up c/w Quick Fit Base

Sale price$112.90 Regular price$125.44
Save 10%

Pay in installments of $31.36 with ShopPay, AfterPay and Klarna

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Sep 3 - Sep 8

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

Description

Kidde Sentry 4x KF21R Optical Smoke & 1x KF31R Heat Alarm Kit Mains Powered with Sealed-In Rechargeable Battery Back-Up c/w Quick Fit BaseKidde Sentry 4x KF21R Optical Smoke & KF31R Heat Alarm Kit with Rechargeable Lithium Battery Back Up The Kidde Sentry Alarm Kit includes four KF21R Optical Smoke Alarms and one KF31R Heat Alarm, providing a complete fire detection solution for larger homes and multi storey residential properties. Designed for mains powered installation, each alarm features a sealed rechargeable lithium battery back up and can be interconnected with up to 23 compatible

Kidde Sentry 4x KF21R Optical Smoke & KF31R Heat Alarm Kit with Rechargeable Lithium Battery Back-Up

The Kidde Sentry Alarm Kit includes four KF21R Optical Smoke Alarms and one KF31R Heat Alarm, providing a complete fire detection solution for larger homes and multi-storey residential properties. Designed for mains-powered installation, each alarm features a sealed rechargeable lithium battery back-up and can be interconnected with up to 23 compatible Kidde FIREX alarms.

When one alarm detects danger, all connected alarms sound simultaneously, helping to provide an early warning throughout the property. This makes the system ideal for improving fire safety across multiple rooms, hallways, landings and escape routes.

Each alarm is supplied with Kidde’s Quick-Fit Slide-On Base for fast installation and features integrated cable management to keep wiring secure and organised. The 150mm flared base plate also provides a neat retrofit finish when replacing older alarms.

Kit Contents

  • 4 x Kidde KF21R Optical Smoke Alarms
  • 1 x Kidde KF31R Heat Alarm

KF21R Optical Smoke Alarm Features

The Kidde KF21R optical smoke alarm is designed to detect slow, smouldering fires caused by electrical faults, furniture or cigarettes. Ideal for circulation routes and living areas, the optical sensor provides dependable early warning protection.

  • Mains-powered optical smoke alarm with sealed rechargeable lithium battery back-up
  • Optical sensor with dust compensation and bug screen
  • Interconnects with up to 23 Kidde FIREX alarms
  • Alarm memory identifies the activated alarm
  • Combined Test/Hush button
  • Auto reset after activation
  • Tamper-resistant locking mechanism
  • Suitable for hallways, bedrooms, lofts and living rooms
  • BSI certified to BS EN14604:2005
  • 10-year warranty

KF31R Heat Alarm Features

The Kidde KF31R heat alarm is ideal for kitchens, garages and loft spaces where smoke alarms may be unsuitable due to cooking fumes, steam or airborne dust. The thermistor heat sensor delivers reliable heat detection while helping reduce nuisance alarms.

  • Mains-powered heat alarm with sealed rechargeable lithium battery back-up
  • Thermistor heat sensor for dependable heat detection
  • Interconnects with up to 23 Kidde FIREX alarms
  • Alarm memory identifies the activated alarm
  • Combined Test/Hush button
  • Auto reset after activation
  • Tamper-resistant locking mechanism
  • Ideal for kitchens, garages and loft spaces
  • BSI certified to BS 5446 Part 2:2003
  • 10-year warranty including battery

Key Benefits

  • Complete smoke and heat alarm solution for larger homes
  • Sealed rechargeable lithium battery back-up for maintenance-free operation
  • Interlinked alarms provide whole-home warning when danger is detected
  • Quick-Fit bases for fast and efficient installation
  • Integrated cable management for neat wiring
  • Suitable for compliance with UK Building Regulations
  • Grade D1 domestic fire alarm system solution
  • Fully compatible with Kidde FIREX smoke, heat and CO alarms

Technical Specifications

KF21R Optical Smoke Alarm

  • Model: KF21R
  • Power Supply: 230V mains with sealed rechargeable lithium battery back-up
  • Sensor Type: Optical
  • Alarm Volume: 85dB minimum at 3 metres
  • Dimensions: 150mm x 150mm x 53mm
  • Weight: 260g
  • Operating Temperature: -10°C to +40°C
  • Warranty: 10 Years

KF31R Heat Alarm

  • Model: KF31R
  • Power Supply: 230V mains with sealed rechargeable lithium battery back-up
  • Sensor Type: Thermistor heat sensor
  • Alarm Volume: 85dB minimum at 3 metres
  • Dimensions: 150mm x 66mm
  • Weight: 245g
  • Operating Temperature: -10°C to +40°C
  • Warranty: 10 Years including battery

Please Note: Alarms are supplied individually within the kit. Installation should be completed by a qualified electrician.

Downloads

KF21R Data Sheet:
Download KF21R Data Sheet

KF31R Data Sheet:
Download KF31R Data Sheet

KF21R Instruction Manual:
Download KF21R Instruction Manual

KF31R Instruction Manual:
Download KF31R Instruction Manual

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 71848446569

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.3 ★★★★★
Based on 9 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
K
Verified Purchase
Krystin
Lake Worth, US
★★★★★ 5
Repeat customer
Size: One Size, Color: Black
These wallets are indestructible...well unless my son loses it, which he does quite often. (Teenagers ammi right 🙄) So I've been a repeat customer. He always asks for another carhartt
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 16, 2026
R
Verified Purchase
Reedo1985
West Palm Beach, US
★★★★★ 5
Tough quality. Nice wallet
Size: One Size, Color: Black
Good wallet. It's a Carhartt so it should last 6 years like my last one
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 24, 2026
A
Verified Purchase
Addison Manley
Phoenix, US
★★★★★ 4
Good quality, bad packaging
Size: One Size, Color: Black
Really good quality. It last a lot time but it came with the lid off. Like it was loose in the box so the packaging was not great but quality is good!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on November 18, 2025
P
Verified Purchase
PJD
Charlottesville, US
★★★★★ 5
SIMPLY PERFECT
Size: 30mm, Color: Brown/Silver-Tone/White/30mm
If you can appreciate a watch that simply tells time, buy this beautiful watch. The band is made of quality leather, it’s easy to adjust to fit and stays in place. The watch face is clean, bright and easy to read the accurate time. The functionality to light the face by pressing the wind button in is a thoughtful feature. The watch is water “resistant” (you can wear the watch when washing dishes), but I wouldn’t shower with it on or submerge it in water just in case. This watch accessorizes with anything I’m wearing in an understated way. TIMEX is a time-proven quality watch maker and this particular watch is a great value! I highly recommend this simply perfect and beautiful watch.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 5, 2026
S
Verified Purchase
Sandra
Draper, US
★★★★★ 5
Love this!
Size: 30mm, Color: Brown/Silver-Tone/White/30mm
Love this. It’s easy to read, but not too big. Just what I wanted. Love the band too!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 13, 2026

recommand products