NM® Marshall® King Split New Arrivals Mattress Accessories
Marshall® is a Canadian name in handcrafted, pocketed-coil sleep. Each Marshall mattress is built in Canada on an 842 tempered pocketed-coil system with high-density encased edge support, spanning the Crafted and Assured series in medium, firm and plush feels, plus matching boxsprings to complete your set. Backed by a 10-year warranty and free next-day delivery in Toronto.
A king box spring is almost always built as two split halves (each 38″ × 80″ — the same footprint as a Twin XL) that sit side by side under your king mattress (76″ × 80″). The split design makes a large king foundation easy to deliver, carry up stairs and set up, and it's exactly what a split-king adjustable base needs so each side can raise and lower independently. Shop split king box springs and foundations matched to Sealy, Serta, Beautyrest, Simmons, Stearns & Foster and more — free delivery across Canada. • What it is: a king box spring built as two 38″ × 80″ halves (each a Twin XL footprint) • Together they support a standard king mattress (76″ × 80″) • Easier to deliver and carry up stairs than a one-piece foundation • Required for split-king adjustable bases (each side adjusts independently) • Brands: Sealy, Serta, Beautyrest, Simmons, Stearns & Foster, Springwall, Galaxy & NM • From $176 — free Canada-wide delivery
See what's new at National Mattress — our latest arrivals, freshly added from the brands you trust. Right now that includes brand-new premium collections like the Beautyrest Centennial Hybrid and the Serta iComfort Zip, bringing the newest comfort technology, updated constructions and fresh designs across plush, medium and firm. New arrivals span every size, and because the lineup refreshes as each season's models land, it's the best place to discover the latest before everyone else. Every new mattress is backed by our 365-night sleep trial, price-match guarantee and free delivery across Canada. • The latest mattresses added to our lineup — refreshed as new models launch • Newest collections now: Beautyrest Centennial Hybrid & Serta iComfort Zip • Latest comfort tech and constructions across plush, medium and firm • Available in every size, from twin XL to king (including split sizes) • Premium and everyday models as they arrive • Every order: 365-night sleep trial, price-match guarantee & free Canada-wide delivery
Complete your sleep setup with pillows, toppers, protectors, and more. These mattress accessories enhance comfort and extend mattress life.
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.
