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Serta iSeries NXG 3500 Medium Mattress - Balanced Cooling Foam Support for All Sleep Positions

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 Medium Foam Mattress is an all-foam mattress built for side, back, and stomach sleepers who want balanced, contouring comfort. High-Density NXG™ Memory Foam and a premium high-density foam core deliver body-hugging cushioning with consistent support, while CoolFeel™ Cover and Carbon Fiber Memory Foam keep it sleeping cool. Backed by a 100-night in-home trial and Serta's 10-Year Limited Warranty.

Serta iSeries NXG 3500 Medium Foam Mattress

All-Foam Comfort, Balanced Support

The 3500 Medium Foam trades coils for an all-foam build, giving it a smoother, more body-hugging feel that absorbs motion and contours closely to your shape. High-Density NXG™ Memory Foam provides deep pressure relief while a premium high-density foam core keeps support consistent underneath.

It's built with CoolFeel™ Cover, Carbon Fiber Memory Foam, High-Density NXG™ Memory Foam, a premium high-density foam core, and Ultimate Edge™ Support.

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

All Sleep Positions

A balanced medium feel and all-foam contouring make this mattress work well for side, back, and stomach sleepers alike.

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 Medium Foam

  • Balanced medium feel — comfortable for side, back & stomach sleepers
  • All-foam, body-hugging comfort — smooth contouring with no coil feel
  • Immediate cooling — cool-to-the-touch cover plus active heat redistribution
  • Superior motion isolation — all-foam construction absorbs movement
  • 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: All-Foam (High-Density NXG™ Memory Foam + Premium High-Density Foam Core)
  • Mattress Height: 13.5 inches
  • Feel: Medium
  • Certification: CertiPUR-US® Certified
  • Warranty: 10-year limited warranty

Engineered for Medium, All-Night Support

Serta iSeries NXG 3500 Medium Foam cutaway showing all-foam construction
Construction

What's Inside

  1. 1 CoolFeel™ Cover — instant cool-to-the-touch comfort that activates immediately upon contact.
  2. 2 Carbon Fiber Memory Foam — actively draws heat away from your body for consistent all-night temperature regulation.
  3. 3 High-Density NXG™ Memory Foam — superior contouring pressure relief with balanced medium support.
  4. 4 Premium High-Density Foam Core — durable, consistent support foundation for long-lasting comfort.
  5. 5 Ultimate Edge™ Support — lasting edge-to-edge stability that maximizes the usable sleep surface.
Feel & Support

Built for a Medium Feel

The 3500 Medium Foam balances contouring comfort with consistent support: High-Density NXG™ Memory Foam cradles the body's curves while the premium high-density foam core maintains proper spinal alignment underneath.

Why it matters:

  • Balanced sink — contouring comfort without losing support
  • All-foam feel — smooth, body-hugging surface with no coil bounce
  • Versatile support — works well for side, back, and stomach sleepers
Temperature Regulation

CoolFeel™ Cooling System

The CoolFeel™ Cover delivers an instantly refreshing cool-to-the-touch sensation, while Carbon Fiber Memory Foam continuously pulls 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: 94.62 lbs

  • Full

    54" wide x 74.5" long
    13.5" High

    Weight: 120.11 lbs

  • Queen

    60" wide x 79.5" long
    13.5" High

    Weight: 140.01 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: 175.69 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: 174.95 lbs

  • Split King (2 mattresses)

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

    Weight: 94.62 lbs (each piece)

*Dimensions of each individual mattress may vary slightly.

SPECIFICATIONS

  • Construction: All-Foam — High-Density NXG™ Memory Foam comfort layers over a Premium High-Density Foam Core (CoolFeel™ Cover, Carbon Fiber Memory Foam, Ultimate Edge™ Support)
  • Mattress Height: 13.5 inches
  • Feel: Medium
  • 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.