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Serta iSeries NXG 3500 Firm Hybrid Mattress (Cooling + 5-Zone Support)

by Serta
Original price $2,599.99 - Original price $5,199.98
Original price $2,599.99
$2,599.99
$2,599.99 - $5,199.98
Current price $2,599.99

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Free Curbside Shipping: 2 Weeks
White Glove Delivery: 3 Weeks
White Glove Delivery + Removal: 3 Weeks

Complete Your Bed

This mattress pairs with a Serta matching foundation or the Beautyrest Black Luxury adjustable base below. Add one using the "Add an Adjustable Base or Matching Foundation" dropdown above, or view full details here.

The Serta® iSeries® NXG™ 3500 Firm Hybrid Mattress pairs a 5-Zone Coil Support System with High-Density NXG™ Memory Foam in a firm feel built for back and stomach sleepers who want minimal sink and stable spinal alignment. CoolFeel™ Cover and Carbon Fiber Memory Foam deliver immediate, all-night cooling, while BestEdge® Support keeps the perimeter stable. Backed by a 100-night in-home trial and Serta's 10-Year Limited Warranty.

Serta iSeries NXG 3500 Firm Hybrid Mattress

Cooling Comfort, Firm Support

The 3500 Firm Hybrid is built for sleepers who want a supportive, minimal-sink surface without giving up pressure relief. A 5-Zone Coil Support System does more of the supporting work in this feel, while the NXG™ Memory Foam comfort layer stays contouring but restrained, keeping the spine aligned for back and stomach sleepers.

It's built with CoolFeel™ Cover, Carbon Fiber Memory Foam, High-Density NXG™ Memory Foam, a 5-Zone Coil Support System, BestEdge® Support, and a high-density foam core foundation.

Built For

Verified Quality

CertiPUR-US® Certified

Every foam layer is tested and certified for content, emissions, and durability, so you can trust what you're sleeping on every night.

Sleep Position

Back & Stomach Sleepers

The Firm feel keeps sink to a minimum, so back and stomach sleepers stay supported and aligned instead of settling into a soft, contouring surface.

Stays Cool

Immediate, All-Night Cooling

A CoolFeel™ Cover delivers instant cool-to-the-touch comfort, while Carbon Fiber Memory Foam pulls heat away from your body throughout the night.

Why You'll Love the iSeries NXG 3500 Firm Hybrid

  • Firm, minimal-sink feel — built for back & stomach sleepers
  • Hybrid comfort & support — coils and NXG™ Memory Foam working together
  • Immediate cooling — cool-to-the-touch cover plus active heat redistribution
  • Reduced motion transfer — less disturbance from a moving partner
  • Reinforced, stable edge — sit and sleep confidently near the perimeter
  • Consistent 13.5" profile — fits standard frames, platform beds, and adjustable bases
  • Split-Head sizing available — independent head-zone adjustability on Queen & King
  • 100-Night In-Home Trial & 10-Year Limited Warranty

Sizes & Specifications

Available Sizes
  • Twin XL
  • Full
  • Queen
  • Split Head Queen
  • King
  • Split Head King
  • Cal King
  • Split King (2 mattresses)
Specifications
  • Construction: Hybrid (5-Zone Coil Support System + NXG™ Memory Foam layers)
  • Mattress Height: 13.5 inches
  • Feel: Firm
  • Certification: CertiPUR-US® Certified
  • Warranty: 10-year limited warranty

Engineered for Firm, All-Night Support

Serta iSeries NXG 3500 Firm Hybrid cutaway showing coil and foam construction
Construction

What's Inside

  1. 1 CoolFeel™ Cover — delivers instant cool-to-the-touch comfort from the moment you lie down.
  2. 2 Carbon Fiber Memory Foam — actively pulls heat away from your body for consistent temperature regulation.
  3. 3 High-Density NXG™ Memory Foam — contouring pressure relief while maintaining firm support.
  4. 4 5-Zone Coil Support System — strategically placed firm and plush zones for back and body alignment.
  5. 5 BestEdge® Support — lasting edge-to-edge stability that expands the usable sleep surface.
  6. 6 High-Density Foam Core Foundation — durable, consistent support for long-lasting comfort.
Feel & Support

Built for a Firm Feel

The 3500 Firm Hybrid keeps sink to a minimum: the 5-Zone Coil Support System does more of the supporting work while High-Density NXG™ Memory Foam contours just enough to relieve pressure at the shoulders and hips without letting you sink in.

Why it matters:

  • Minimal sink — supportive surface for back and stomach sleepers
  • Coil-forward feel — less body-contouring than a medium or plush feel
  • Consistent alignment — zoned coils support the lumbar region all night
Temperature Regulation

CoolFeel™ Cooling System

The CoolFeel™ Cover provides an immediate cool-to-the-touch sensation, while Carbon Fiber Memory Foam continuously draws heat away from your body throughout the night, keeping temperature balanced from bedtime through morning.

Why it matters:

  • Faster sleep onset — a cool surface helps you fall asleep quicker
  • Fewer temperature wake-ups — heat is actively redistributed all night
Made to Last

Certified Safe, Backed for the Long Haul

CertiPUR-US® Certified: every foam layer is tested for content, emissions, and durability. 100-Night In-Home Trial: try it risk-free at home. 10-Year Limited Warranty: your investment is protected for years of use.

MATTRESS DIMENSIONS

  • Twin XL

    39" wide x 79.5" long
    13.5" High

    Weight: 105.41 lbs

  • Full

    54" wide x 74.5" long
    13.5" High

    Weight: 134.01 lbs

  • Queen

    60" wide x 79.5" long
    13.5" High

    Weight: 158.34 lbs

    Split-Head sizing available (Split Head Queen) — same footprint, independent head-zone adjustability, not a separate mattress pair.

  • King

    76" wide x 79.5" long
    13.5" High

    Weight: 196.66 lbs

    Split-Head sizing available (Split Head King) — same footprint, independent head-zone adjustability, not a separate mattress pair.

  • Cal King

    72" wide x 83.5" long
    13.5" High

    Weight: 196.19 lbs

  • Split King (2 mattresses)

    39" wide x 79.5" long (each piece)
    13.5" High

    Weight: 105.41 lbs (each piece)

*Dimensions of each individual mattress may vary slightly.

SPECIFICATIONS

  • Construction: Hybrid — High-Density NXG™ Memory Foam comfort layers over a 5-Zone Coil Support System (CoolFeel™ Cover, Carbon Fiber Memory Foam, BestEdge® Support, high-density foam core foundation)
  • Mattress Height: 13.5 inches
  • Feel: Firm
  • Certification: CertiPUR-US® Certified
  • Warranty: 10-year limited warranty
  • Care: Use a mattress protector; do not apply liquids directly to the mattress. Spot clean with baking soda on soiled areas, let stand 15 minutes, vacuum, and air dry. Rotate periodically for even wear.

10 Year Limited Warranty

Serta® mattresses or foundations used with proper support are protected by a 10 year limited manufacturer’s warranty. Serta products are warrantied against manufacturing defects in workmanship and material (excluding covers and handles, except for handles on iSeries and equivalent level mattresses).

Exclusions

    Comfort Preference
  • Bedding sold “as is”, or floor samples, or bedding purchased from second hand parties, non-retail establishments or received as a promotional item.
  • Bedding height
  • Corner guards
  • Bent perimeter border rods due to moving or bending the sleep set for innerspring models
  • Replacement of another piece in a sleep set unless it is also defective
  • Damage of the mattress or foundation due to misuse or abuse
  • Mattress damage due to an inappropriate foundation or when an incorrect bed frame is used
  • Sheet fit
  • Fabric Stains, soiling, fluid penetration, tears or burns
  • Adjustable foundations (see owner’s manual for details on warranty coverage)
  • Mattress fabric (except as noted in the Warranty Coverage Detail section for an All Foam mattress)
  • Zippered mattress cover damage due to improper care including removal of cover
  • Normal change in softness and recovery time associated with memory foam and latex materials over time. This does not affect the pressure relieving qualities of these materials.
  • Body impressions in the mattress that measure less than ¾" for all smooth top (non-quilted) hybrid mattresses and All Foam model mattresses.
  • Sagging in the mattress that measure less than less than ¾" for all smooth top (non-quilted) hybrid mattresses and All Foam model mattresses.

Term

The warranty coverage runs from the original date of purchase. Replacement of the mattress or foundation does not extend its limited warranty or begin a new limited warranty period. Your warranty period is based on the code printed on your white law label as indicated on the Warranty Code Chart. The duration of any applicable implied warranties, including but not limited to the implied warranties of merchantability and fitness, shall not exceed the term of this limited warranty. (Some states do not allow limitations on how long an implied warranty lasts, so this limitation may not apply to you.) Serta® shall not be liable for incidental or consequential damages that result from the use of your Serta® product. (Some states do not allow the exclusion or limitation of incidental or consequential damages, so this exclusion may not apply to you.) No expressed or implied warranties are extended to persons who purchase the product from anyone other than Serta Simmons Bedding Company or its authorized dealers, and all warranties to such persons, including the implied warranties of merchantability and fitness, are hereby excluded.

Service

If your Serta® mattress or foundation fails due to a manufacturing defect, the exclusive remedy under this warranty will be replacement of the defective product in the U.S., Puerto Rico or U.S. Virgin Islands. If the Serta® product you purchased is discontinued at the time of replacement, a current model of comparable quality and value will be selected. To receive service under the terms of this warranty contact your original Serta® dealer. If your original Serta® dealer is no longer in business or you have moved outside the service area, please contact Serta Customer Service at 1-888-55-SERTA (1-888-557-3782) between the hours of 9am to 5pm EST Monday - Friday. A copy of original bill of sale is needed to determine original date of purchase. Model name label and law label must be provided to identify the bedding and validate this warranty.

Your Rights Under State Law

This warranty gives you specific rights, and you may have other rights, which vary from state to state. This warranty is extended only to the original purchaser from Serta Simmons Bedding Company or its authorized dealers.