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Features you'll love

Support System

Pocket Springs

Individually pocketed springs work to give you support exactly where you need it.

Comfort Fillings

Cool Gel Memory Foam

Infused with gel microbeads to regulate temperature, while also improving breathability.

Firmness

Soft

Good for side sleepers. A softer level of support.

Amy Curtis

Marketing Director, Sleepeezee

What the Sleep Expert thinks...

"For sink-in softness with serious tech underneath, choose ActivFlex 3600. Three spring tiers, ActivFlex™ foam and twin StayCool™ Gel layers align, contour and cool simultaneously. Mini springs in the pillow-top refine pressure relief, while the one-sided build keeps upkeep simple."

Description

For sumptuous full-body cushioning paired with innovative support, discover the Sleepeezee ActivFlex Response 3600 Memory Mattress, designed by the UK's leading sleep manufacturer.

Innovative support for enhanced posture control

A core unit of a combination of mini comfort springs and full-size traditional pocket springs provides targeted support to key areas of your body, ensuring you receive essential posture control. An innovative layer of ActivFlex™ spring foam combines the benefits of both of these supportive features, providing precise pressure relief to your body while effortlessly moulding to it like foam. These support systems, with an additional layer of up to 1000 mini comfort springs in the pillow top of this mattress, provide incredible support without compromising the soft feel of your sleep surface.

Cooling comfort at every point of contact

Also within the sumptuous pillow top layer of this mattress - which acts as a gorgeously comfortable mattress topper - is a layer of Staycool™ gel. This cooling gel actively draws heat away from your body, providing a consistently refreshing sensation from head to toe. In fact, you'll find two layers of this clever material within your Sleepeezee ActivFlex Response 3600 Memory Mattress, making it an exceptionally breathable, cool foundation for sleep.

Full-body softness for a sink-in feeling

Soft polyester comfort layers provide additional full-body cushioning, letting you enjoy that weightless 'sink in' feeling your body craves after a long, tiresome day. A luxuriously soft knitted cover finishes this mattress with a final touch of sumptuousness, while the one-sided, no-turn design of the mattress makes regular care a breeze.

1278720-5063475047258

Features

3600 Pocket Springs

Pocket springs are springs mounted in their own separate fabric pockets, meaning they work completely independently of one another and can provide your body with better pressure relieving support.

Staycool™ Gel

Staycool™ Gel helps to manage moisture levels within the mattress, which aids temperature regulation so you won't feel too hot in warmer months.

ActivFlex™ Spring Foam

Designed to mimic the precise support and movement of pocket springs while moulding to your body as a foam, this innovative material combines the benefits of both.

33cm Depth

This mattress is approximately 33cm deep.

Soft Knitted Cover

Highly breathable and soft to the touch, this cover finishes the mattress with a truly luxurious feel.

No Need To Turn

A single-sided mattress which does not need to be turned/flipped. One-sided mattresses should, however, be rotated head to toe regularly.

Pillow Top

Pillow top mattresses have the benefit of an additional pillow layer of plush fillings on the top of the mattress, which provides extra luxurious comfort.

No Roll Together

Individual personal sleeping zones mean that you won't be disturbed if your partner rolls or moves, as you won't feel their motion. There's also no tendency to roll towards the middle of the mattress.

Pressure Relieving

This type of mattress gives maximum pressure relief, allowing your body weight to spread across it evenly. This ultimately means less tossing and turning throughout the night and a more relaxing and restful sleep.

Turning Handles

Flag-stitched handles are attached to the sides of the mattress to assist in turning or rotating.

Hypoallergenic

Being hypoallergenic, this is the perfect item for allergy sufferers - or anyone looking for a healthy night's sleep.

Vegan Friendly

This product is made from materials that are 100% free from animal by-products.

Flat Mattress

This mattress will arrive flat, not rolled and boxed.

Made in the UK

This item has been manufactured in the UK.

Fire Resistant - Low Hazard

This product conforms to the BS7177: 2008 standard for domestic use (low hazard) - ideal for use at home.

Additional features

Made by an NBF-Approved ManufacturerPeace of mind and reassurance - the manufacturer of this item is an approved member of the National Bed Federation.

Benefits

A combination of innovative springs target precise support to key areas of your body
Cleverly engineered ActivFlex™ spring foam provides an even closer level of support as it contours your shape
Staycool™ gel actively draws heat away from your body for consistent freshness through the night
The sumptuously soft pillow top design allows you to sink into the mattress with a weightless feel
Enhanced full-body cushioning ensures you stay blissfully comforted and properly supported all night long

Expert Approved

You've got the best price

As Online Bed Retailer of the Year 2025 - 2026, you can trust us to get you the best price. With our fast delivery and exceptional service, you won't find better elsewhere.

Sleepeezee ActivFlex Response 3600 Memory Mattress

5.0 out of 5

5 Star (1)

4 Star (0)

3 Star (0)

2 Star (0)

1 Star (0)

Experience blissful comfort and support for a refreshing night's sleep.

3600 Pocket Springs

ActivFlex™ Spring Foam

Staycool™ Gel

33cm Depth

Firmness: Soft

£719

RRP £1039

Save £320

from £719

Size

Single 3' x 6'3"

£719 RRP £1039

1-2 Weeks

Small Double 4' x 6'3"

£969 RRP £1399

1-2 Weeks

Double 4'6" x 6'3"

£969 RRP £1399

Only 1 left

King Size 5' x 6'6"

£1079 RRP £1559

Only 2 left

Super King 6' x 6'6"

£1389 RRP £2039

1-2 Weeks

Super King Zip & Link 6' x 6'6"

£1569 RRP £2289

1-2 Weeks

FREE Delivery within Next Day

FREE delivery Tomorrow, 6th March
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Description & Features

For sumptuous full-body cushioning paired with innovative support, discover the Sleepeezee ActivFlex Response 3600 Memory Mattress, designed by the UK's leading sleep manufacturer.

Innovative support for enhanced posture control

Cooling comfort at every point of contact

Full-body softness for a sink-in feeling

3600 Pocket Springs

Pocket springs are springs mounted in their own separate fabric pockets, meaning they work completely independently of one another and can provide your body with better pressure relieving support.

Staycool™ Gel

Staycool™ Gel helps to manage moisture levels within the mattress, which aids temperature regulation so you won't feel too hot in warmer months.

ActivFlex™ Spring Foam

Designed to mimic the precise support and movement of pocket springs while moulding to your body as a foam, this innovative material combines the benefits of both.

33cm Depth

This mattress is approximately 33cm deep.

Soft Knitted Cover

Highly breathable and soft to the touch, this cover finishes the mattress with a truly luxurious feel.

No Need To Turn

A single-sided mattress which does not need to be turned/flipped. One-sided mattresses should, however, be rotated head to toe regularly.

Pillow Top

Pillow top mattresses have the benefit of an additional pillow layer of plush fillings on the top of the mattress, which provides extra luxurious comfort.

No Roll Together

Pressure Relieving

Turning Handles

Flag-stitched handles are attached to the sides of the mattress to assist in turning or rotating.

Hypoallergenic

Being hypoallergenic, this is the perfect item for allergy sufferers - or anyone looking for a healthy night's sleep.

Vegan Friendly

This product is made from materials that are 100% free from animal by-products.

Flat Mattress

This mattress will arrive flat, not rolled and boxed.

Made in the UK

This item has been manufactured in the UK.

Fire Resistant - Low Hazard

This product conforms to the BS7177: 2008 standard for domestic use (low hazard) - ideal for use at home.

A combination of innovative springs target precise support to key areas of your body
Cleverly engineered ActivFlex™ spring foam provides an even closer level of support as it contours your shape
Staycool™ gel actively draws heat away from your body for consistent freshness through the night
The sumptuously soft pillow top design allows you to sink into the mattress with a weightless feel
Enhanced full-body cushioning ensures you stay blissfully comforted and properly supported all night long

Additional features

Made by an NBF-Approved ManufacturerPeace of mind and reassurance - the manufacturer of this item is an approved member of the National Bed Federation.

1278720-5063475047258

Sleepeezee 10 Year Guarantee

Sleepeezee 10 Year Guarantee

Sleepeezee are confident that all of their beds and mattresses are made to the highest standards. Therefore they offer a 10 year guarantee across their entire range of mattresses and divan bed sets.

Download warranty/guarantee information

100 Night Sleep Trial

Finding the perfect mattress shouldn't be stressful. That's why we offer a generous 100 night sleep trial. Snuggle in and test it out for at least 50 nights. If it's not your perfect match we’ll offer you an exchange for a mattress that you love even more.

Delivery & Recycling

We provide our award-winning Free Next Day Delivery service to most locations, sending a proper night’s sleep out far and wide. Hassle-free and convenient, you can even choose a time and day that suits you, have us take your old mattress away for recycling, and get us to deliver to your room of choice!

In some places, a small fee will be charged to help us get you your best night’s rest as quickly as possible. Take a look at the following postcodes to see if this applies to you, and if you’re not sure, then use our helpful Postcode Checker to help you shop with confidence.

AB10-AB16, AB21-AB25, AB30-AB39, AB41-AB45, AB51-AB56
CA1-CA9
DD1-DD11
DG1-DG14, DG16
EH1-EH49, EH51-EH55, EH91, EH95, EH99
FK1-FK21
G1-G5, G9, G11-G15, G20-G23, G31-G34, G40-G46, G51-G53, G58, G60-G79, G18-G84, G90
IV1-IV19, IV30-IV32, IV36
KA1-KA30
KY1-KY16, KY99
LA1-LA7
ML1-ML12
PH1-PH26
TD1-TD15

Old Mattress Removal

For just £39, our fast and friendly team will collect your old mattress at the exact same time we deliver your new one. No waiting, no heavy lifting, and no clutter. 100% of your old mattress is carefully recycled and kept out of landfill. Simply select 'Old Mattress Removal' at checkout.

Sustainability

Your order helps us plant trees

151,670+ Trees planted so far

Rated Excellent

5.0/5

based on 1 reviews

Comfort Rating

5 / 5

5 Star 100%

4 Star 0%

3 Star 0%

2 Star 0%

1 Star 0%

Reviews with images

A customer photo for Sleepeezee ActivFlex Response 3600 Memory Mattress - After struggling with hip pain, changing our mattress to the sleepeezee activfle. Author: Customer. Dated: 2025-12-01

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After struggling with hip pain, changing our mattress to the sleepeezee activflex 3600 response has been a real game changer! having the best nights sleep and sleeping through the night again!

User Generated Content - An image regarding this review

Customer 1st Dec

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Sleepeezee ActivFlex Response 3600 Memory Mattress

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*Delivery charges may apply for some areas. Please see our delivery page for more information.
1. Order by 6pm for next day delivery between Monday-Friday, 12pm on Saturday and 3pm on Sunday. The 'Order by' time may be subject to change dependant on our delivery partners.

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MattressNextDay, 116 Joseph Wilson Industrial Estate, Whitstable, Kent, CT5 3SN

We value your privacy

Features you'll love

Amy Curtis

What the Sleep Expert thinks...

Innovative support for enhanced posture control

Cooling comfort at every point of contact

Full-body softness for a sink-in feeling

Additional features

Sleepeezee ActivFlex Response 3600 Memory Mattress

Innovative support for enhanced posture control

Cooling comfort at every point of contact

Full-body softness for a sink-in feeling

Additional features

Old Mattress Removal

Need help?

Rated Excellent

Reviews with images

Frequently paired with

More Soft Mattresses

More with Pocket Springs

More from Sleepeezee

You might also like

More to explore

Your order helps us plant trees

Free, fast delivery

Mattress recycling

0% Interest finance

Sleepeezee ActivFlex Response 3600 Memory Mattress

£

Pair it with

After struggling with hip pain,…