Serta iSeries NXG 3500 13.5 inch firm hybrid mattress in a modern bedroom with cooling cover.

Interior layers of Serta iSeries NXG 3500 firm hybrid mattress showing coil system and support foam.

Serta iSeries NXG 3500 13.5" firm hybrid mattress with a moisture-wicking cooling fabric cover.

Side view of Serta iSeries NXG 3500 firm mattress showing high-quality edges and durable construction.

Close-up of the cooling geometric pattern on the Serta iSeries NXG 3500 firm hybrid mattress cover.

Side sleeper on Serta iSeries NXG 3500 firm hybrid mattress showing spinal alignment and support.

Serta iSeries NXG 3500 firm hybrid mattress scale, ideal for back sleepers needing a stable surface.

Serta iSeries NXG 3500 hybrid mattress diagram showing lumbar support and targeted pressure relief.

Serta iSeries NXG 3500 Hybrid Firm 13.5 Inch Mattress

Plush Medium Firm Pillow top Memory foam Hybrid

Serta iSeries NXG 3500 Hybrid Firm 13.5 Inch Mattress

$2,599.00

$3,499.00

Save $900.00

Brand:

Serta

i Size Guide

$2,599.00

Only 17 left in stock

Free USA Wide Delivery

10 Year Warranty

Advanced Technology

To begin with, the mattress greets you with a CoolFeel knit cover that wicks heat and moisture for a fresh first touch. Next, layers of NXG Next Generation Memory Foam and Gel Action memory foam layers deliver firm contouring that many owners call the best 13.5 inch firm mattress for back pain.

Because these foams rest on a Duet Coil-in-Coil Support System, you gain maximum spinal alignment support while enjoying a touch of bounce that heavy sleepers appreciate.

Individually wrapped inner and outer springs absorb energy, giving reduced partner motion transfer even when one sleeper turns. A high-density foam encasement steadies every side so you can sit or sleep to the very edge.

Finally, you can Buy Serta iSeries NXG 3500 online today, claim free USA shipping, flexible Affirm payments, and a risk-free 120-night trial while the holiday sale lasts.

Firm Hybrid Alignment

Duet coils keep the spine level while dense foam reduces sag.

5-Zone Pressure Relief

Zoned push-back under shoulders, lumbar, and hips balances comfort.

Heat-Wicking Gel Foam

Conductive particles move warmth away for heat-wicking breathable comfort.

Motion-Quiet Springs

Pocketed coils limit energy transfer, so couples rest undisturbed.

Ultimate Edge Stability

Perimeter foam stops roll-off and expands usable surface.

Sale plus Financing

Live markdown and Affirm payments simplify budgeting.

Key Mattress Benefits

6 Layers
Of Cooling
Comfort

Breathable fibres keep the surface cool and dry.

Contours precisely while transferring heat away for steadier temperature.

Deepens pressure relief and reinforces the firm feel.

Spreads body weight evenly and buffers the coil unit.

Inner micro-coil nested inside an outer coil delivers adaptive lift and zoned alignment.

Robust rails strengthen edges for lasting durability and full-surface use.

DISCOVER WHY BUYING WITH

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HAVE QUESTIONS?

WE'VE GOT ANSWERS

Designed for deep comfort and better rest, so you wake up refreshed and ready for the day

Yes. The firm comfort and Duet coil core keep hips elevated and the lumbar region supported, which can ease morning stiffness.

Gel-infused NXG foam and a ventilated coil core help move heat away, so it sleeps cooler than traditional firm memory-foam beds.

Yes. The flexible hybrid construction bends smoothly on most adjustable foundations. Keep slats under three inches apart for best support.

iSeries blends pocketed coils with NXG foams for hybrid buoyancy and airflow, whereas iComfort models are all-foam for deeper contour and lower motion transfer.

Standard fitted sheets with a pocket depth of 15–18 inches usually accommodate the 13.5-inch profile.

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