King Medium Innerspring Back Sleeper Adjustable Base Compatible Black All Mattresses
King mattresses measure 76" × 80" — the widest standard size, giving each partner the same personal space as a twin. They're the top choice for couples who want maximum room, families who co-sleep, and larger master bedrooms. Compare every king option below by brand, feel, and price.
Medium mattresses balance cushioning and support — soft enough to relieve pressure, firm enough to keep your spine aligned. This medium-firm feel is the most universally comfortable choice, suiting combination sleepers, couples with different preferences, and most back and side sleepers. Compare every medium option below by brand and profile.
Innerspring mattresses use a coil support system for a responsive, bouncy feel with strong airflow that sleeps cool. They deliver reliable edge support and a classic "on top of the bed" feel at an accessible price — a fit for back, stomach, and combination sleepers. Compare every innerspring option below.
Back sleepers do best on a mattress that supports the lower back while gently following the spine's natural curve — typically a medium to medium-firm feel. The options below balance support and pressure relief for back sleepers. Compare them by brand, feel, and profile.
These mattresses are built to flex with adjustable bed bases — bending smoothly at the head and foot without damage — so you can raise, recline, and find your ideal position. Compare every adjustable-base-compatible option below by brand, type, and feel.
Medium mattresses balance cushioning and support — soft enough to relieve pressure, firm enough to keep your spine aligned. This medium-firm feel is the most universally comfortable choice, suiting combination sleepers, couples with different preferences, and most back and side sleepers. Compare every medium option below by brand and profile.
Innerspring mattresses use a coil support system for a responsive, bouncy feel with strong airflow that sleeps cool. They deliver reliable edge support and a classic "on top of the bed" feel at an accessible price — a fit for back, stomach, and combination sleepers. Compare every innerspring option below.
Back sleepers do best on a mattress that supports the lower back while gently following the spine's natural curve — typically a medium to medium-firm feel. The options below balance support and pressure relief for back sleepers. Compare them by brand, feel, and profile.
These mattresses are built to flex with adjustable bed bases — bending smoothly at the head and foot without damage — so you can raise, recline, and find your ideal position. Compare every adjustable-base-compatible option below by brand, type, and feel.
Shop 200+ mattresses from Serta, Beautyrest, Sealy, Tempur-Pedic, Springwall, and Stearns & Foster at National Mattress — available in Single/Twin through King sizes from $99 to $6,640. Choose from innerspring, euro-top, memory foam, hybrid, and latex constructions in four firmness levels from extra firm to plush. Every mattress is manufactured in Canadian factories using CertiPUR-US® certified foams and ships free across Canada with a 365-night sleep trial, price match guarantee, and manufacturer warranty coverage up to 25 years.
Loading recommendations...
Navigating through the elements of the carousel is possible using the tab key. You can skip the carousel or go straight to carousel navigation using the skip links.
![]()
![]()
![Online availability icon]()
Only left!
![In-Store availability icon]()
On Display:
![Free delivery availability icon]()
Free delivery as soon as
![Pickup available icon]()
Only Pickup available to
SOLD OUT
Compare at
Compare at
Upgrade your sleep at National Mattress
Discover a mattress that transforms your sleep into a truly rejuvenating experience. We offer a wide variety of options to suit every sleep style and preference, ensuring a better night's sleep.
Why Choose Us?
- Variety: From plush to firm, we have options for every body type and sleep style.
- Quality: Trusted brands and top-notch materials for long-lasting comfort.
- Sleep Trials & Warranties: Enjoy peace of mind with flexible trials and warranties.
- Expert Advice: Get personalized recommendations from our sleep specialists.
Mattress Selection Includes
- Memory Foam: Contours to your body for personalized comfort and pressure relief.
- Hybrid: Combines responsive springs with foam for balanced support and comfort.
- Innerspring: Provides firm support, bounce, and cooling airflow.
- Latex: Hypoallergenic, eco-friendly, and exceptionally comfortable.
- Adjustable Beds: Customize your sleep position for optimal comfort.
Filters
Loading recommendations...
Navigating through the elements of the carousel is possible using the tab key. You can skip the carousel or go straight to carousel navigation using the skip links.
![]()
![]()
![Online availability icon]()
Only left!
![In-Store availability icon]()
On Display:
![Free delivery availability icon]()
Free delivery as soon as
![Pickup available icon]()
Only Pickup available to
SOLD OUT
Compare at
Compare at