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]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 639643203

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4.5 ★★★★★
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Mother of M.M.
Battle Creek, US
★★★★★ 5
Fantastic satin pillow cases for the price
Size: Queen (20" X 30"), Color: 02 - Pure White, Number of Items: 2
Edit: I already put five stars in the first place, but I was unfair to these pillow cases in my initial review! I thought they were a little warmer than the natural silk, because I was sleeping on them with acrylic pyjamas on. I have come to realise the pillow cases are not warm. They are truly excellent in every way. I just get sweaty every time I wear acrylic pyjamas! I have already ordered two more sets of these (and have switched to micrfibre pyjamas)! Original review: First off, I want to address a popular misconception. Satin is a weave, not a fibre. So polyester satin is real satin, and it is very common. To all the people saying the makers lied about the fabric, they absolutely did not! I bought these and I bought some inexpensive silk ones at the same time. I have been loving the silk ones and only started using these lately. I'm happy with all of them. These are not silk, and I can feel the difference, but they are a nice, smooth polyester satin. The white colour is indeed a pure white. I machine washed mine and hung them to dry. They did not wrinkle, pick or pill, and they did not change in colour or size. They look fresh and pristine. I measured my pillows and got the right size. They are pretty and neat, they seem to be well sewn and well finished, with no hanging threads. They are very soft to sleep on and did not make my dry, curly hair frizz up. I slept on them without my protective bonnet, so I got the full experience! Honestly, with the smooth, tight weave of the fabric, they may be superior to the real silk in terms of babying my skin and hair. However, they are a little bit warmer. That is fine for now, since the weather is cool. I might just use these while it is cool out and switch to silk in summer, or I might continue to alternate, we will see. Overall, I am happy with my purchase and would buy them again.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 3, 2026
J
Verified Purchase
Jaclyn P.
Boise, US
★★★★★ 5
Amazing Pillowcases — Sleep Better Every Night!
Size: Queen (20" X 30"), Color: 05 - Dark Grey, Number of Items: 2
The Bedsure Satin Pillowcases (2-Pack) are hands-down one of the best small upgrades I’ve made to my sleep routine. They feel luxuriously smooth — almost like silk — but are much more affordable and easy to care for. The satin surface feels gentle on your skin and hair, and I really notice the difference in reduced friction compared to regular cotton cases. What I love most: 🌬️ Cooling & Comfortable: These pillowcases stay cool and breathable all night — perfect for hot sleepers or warm weather. 💁‍♀️ Hair & Skin Friendly: My hair isn’t as tangled in the morning, and my skin feels softer with fewer sleep creases. 🛏️ Beautiful & Practical: The dark grey color looks great with my bedding, and the envelope closure keeps the pillow snug without zippers to snag hair or wash fabrics. 🎁 Perfect Gift: Comes as a 2-pack and makes a thoughtful gift for anyone — women, men, roommates, or newlyweds. They wash well and hold up without pilling or losing their silky feel. Great quality at a great price — these pillowcases are definitely worth it if you want a little luxury in your everyday sleep!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 1, 2026
J
Verified Purchase
Jacque Guzman
Grantham, US
★★★★★ 5
Satin pillowcases
Size: Standard (20" X 26"), Color: 09 - Ivory, Number of Items: 2, Size: Standard (20" X 26"), Color: 09 - Ivory, Number of Items: 2
These pillowcases are honestly a great purchase. They feel incredibly smooth and soft and I noticed a real difference in both my hair and skin! my hair is less frizzy in the morning, and my skin feels softer. The quality is excellent for the price, and they’ve held up well after several washes without losing their softness or color. They also feel cool and comfortable throughout the night, which is a nice bonus. Overall, I’m really happy with this purchase and would definitely recommend them to anyone looking to upgrade their sleep experience!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 28, 2026
J
Verified Purchase
Julia Taylor
Lowell, US
★★★★★ 5
Great for my frizzy hair
Size: Queen (20" X 30"), Color: 06 - Black, Number of Items: 2
I got these because I really wanted something to helps tame my frizzy hair but also help with my skin. I have very sensitive skin and my break outs have reduced so much! They fit my standard pillows without an issues. The color never fades, they wash and dry well. The quality is on point. Worth it.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 17, 2026
A
Verified Purchase
Amazon customer
Massapequa, US
★★★★★ 5
Great quality & colors
Size: Body (20" X 54"), Color: 03 - Beige, Number of Items: 1
Good price so is easier to buy several colors. Perfect fit for a body pillow. Super there are pillow cases to match. Soft! Great quality.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 25, 2026

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