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

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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

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4.6 ★★★★★
Based on 25 reviews
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Product Reviews
A
Verified Purchase
Amazon Customer
Pawtucket, US
★★★★★ 5
Dogs love them
3 dogs all fight over these bones
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 1, 2023
S
Verified Purchase
Shelli Williamson
New York, US
★★★★★ 2
After 2 weeks update 9 month review
Updated. 9 months of aggressive chewing. Pic 2 - Purchased this 2 weeks ago. I have two Pitties. An 8 yr old 80lbs and a 2 yr old 45 lbs. Little pieces flake off as they chew. It is hard finding tough toys for very aggressive chewers. I’m not impressed by these. However, the dogs do love them.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on July 29, 2023
A
Verified Purchase
artistgirl
Pawtucket, US
★★★★★ 5
Dog love them
Great dog are kept busy
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Reviewed in the United States on June 18, 2023
T
Verified Purchase
Timothy G
Lowell, US
★★★★★ 5
Chew incessant dogs
Color: 1PC-Beef-Red
Very tough, My Dashound is a Tasmanian Devil & young this has really slowed his roll, and still enjoying the chewing & licking with peanut butter. Great item!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 1, 2026
M
Verified Purchase
Matthew Nichter
Alexandria, US
★★★★★ 5
Durable!
Color: 1PC-Beef-Red
Alright, here's a product review for those Tough Dog Toys: Finally, a Toy That Survives My Monster! - Tough Dog Toys Review As the owner of a determined (and I mean determined) large breed chewer, finding toys that last longer than five minutes has been a constant and often frustrating quest. I've gone through countless plush toys ripped to shreds, rubber toys with chunks missing, and even some "indestructible" toys that met their demise far too quickly. That's why I was both hopeful and skeptical when I came across the Tough Dog Toys, designed specifically for aggressive chewers and large breeds. Let me tell you, these bone-shaped nylon toys are living up to their name. My power-chewing Labrador has been going at this thing for days now, and I'm genuinely impressed. Where other toys have succumbed to his relentless gnawing, the Tough Dog Toy has held its own. There are some minor teeth marks, as expected, but absolutely no significant damage, no pieces torn off, and no signs of imminent destruction. "Almost indestructible" might actually be an understatement! The design is simple but effective. The solid nylon construction feels incredibly durable, and the bone shape is easy for my dog to grip and maneuver. It's also a good size for a large breed – substantial enough that he can really get a good chew going without it disappearing in his mouth. What I appreciate most is the peace of mind this toy provides. I no longer have to constantly supervise playtime, fearing that he'll ingest pieces of a destroyed toy. This feels like a safe and long-lasting option for even the most enthusiastic chewers. Pros: * Truly durable – stands up to aggressive chewing from a large breed. * Solid nylon construction feels virtually indestructible. * Safe design with no small parts to break off. * Good size and shape for large dogs to grip and enjoy. * Provides long-lasting entertainment. Cons: * May show some teeth marks over time (though this hasn't compromised its integrity). * It's a fairly hard material, so dogs who prefer softer toys might not be as interested. Overall: If you're at your wit's end trying to find a toy that can withstand your aggressive chewing large breed dog, I highly recommend giving the Tough Dog Toys a try. This bone toy has proven to be the most durable option we've encountered, offering excellent value for money and, most importantly, a safe and engaging chewing experience for your furry friend. Five out of five paws!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 23, 2025

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