SKU: 639643203

Kidde Sentry 2x 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 2x KF21R Optical Smoke & 1x KF31R Heat Alarm Kit Mains Powered with Sealed-In Rechargeable Battery Back-Up c/w Quick Fit BaseKidde Sentry 2x KF21R Optical Smoke & 1x KF31R Heat Alarm Kit with Rechargeable Lithium Battery Back Up The Kidde Sentry Alarm Kit combines two KF21R Optical Smoke Alarms and one KF31R Heat Alarm to provide dependable whole home fire detection for 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. This

Kidde Sentry 2x KF21R Optical Smoke & 1x KF31R Heat Alarm Kit with Rechargeable Lithium Battery Back-Up

The Kidde Sentry Alarm Kit combines two KF21R Optical Smoke Alarms and one KF31R Heat Alarm to provide dependable whole-home fire detection for 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.

This advanced alarm system delivers reliable smoke and heat detection across hallways, bedrooms, living spaces, kitchens and loft areas, helping properties comply with UK Building Regulations while enhancing occupant safety.

Each alarm is supplied with Kidde’s Quick-Fit Slide-On Base for faster installation, while integrated cable management ensures neat and secure wiring. The 150mm flared base plate also provides a clean finish during retrofit installations.

Kit Contents

  • 2 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 escape 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 designed for kitchens, garages and loft spaces where smoke alarms may be unsuitable due to cooking fumes, dust or steam. The thermistor heat sensor provides reliable heat detection while reducing nuisance alarms.

  • Mains-powered heat alarm with sealed rechargeable lithium battery back-up
  • Thermistor heat sensor for reliable 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 system for residential properties
  • Sealed rechargeable lithium battery back-up for maintenance-free protection
  • 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 carried out 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]
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SKU: 639643203

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Mary Hales
Los Angeles, US
★★★★★ 5
Soft and cooling
Color: Dark Grey, Size: 2 Pack Queen(20x30)-Regular
Soft, not too thick and wash very well. Feels great against my skin and doesn’t make my hair frizzy. Color was perfect.
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Reviewed in the United States on May 13, 2026
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Issyr
Belleville, US
★★★★★ 3
Not soft, not wrinkle free
Color: Light Grey, Size: 2 Pack King(20x36)-Regular, Color: Light Grey, Size: 2 Pack King(20x36)-Regular
Not as soft as expected. Major WRINKLED after washer/dryer. Always use max heat on dryer. Not as described. Money wasted.
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Reviewed in the United States on April 30, 2026
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Billy Ragsdale
Pawtucket, US
★★★★★ 5
These pillowcases are wonderful.
Color: Light Purple, Size: 2 Pack Queen(20x30)-Regular
I love my new pillowcases. They are cooling and easy to wash.
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Reviewed in the United States on June 4, 2026
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Kindle Customer
Phoenix, US
★★★★★ 5
Soft and cool.
Color: Cooling Blue Cover, Size: Queen (Pack of 2)
Love this pillow set. Comfortable addition and nice and cool at all times. Going to be great for when the hot weather hits
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Reviewed in the United States on June 8, 2026
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Anna T
Grantham, US
★★★★★ 5
As advertised for once! Lol
Color: Cooling Blue Cover, Size: Queen (Pack of 2), Color: Cooling Blue Cover, Size: Queen (Pack of 2)
Queen size set of 2 pillows, I'm giving it 5stars first bc it has a good length and width!! If you've ever bought memory foam pillows before you know some are small!! Anyways after having it for 5nights, we loved that me and my huddy could adjust the Thickness amount we had in it to our needs, me needing a thick pillow and my husband needing a flatter one. So this was perfect for that. So far its nice to sleep on, stays cool, doesnt get hot. I would say its on the frimer side but softer the more foam you take out! Really its just good for the amount you spend!! Will it last 10years probably not but what does now a days. This is the only time my huddy n I bought the same pillow and both love it so I'm just still in shock it worked out so well!!
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Reviewed in the United States on April 28, 2026

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