Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant’s customer service levels, popularity trends, and more. The rankings reflect our opinion and should be a good starting point for shopping. By purchasing the products we rank, you’ll get the lowest price we found while we may receive a commission at no cost to you, which will help us continue to provide you with value.
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10 Best firm mattress in a box kings of 2025
Save up to 33% off
Best Choice1
BedStoryBedStory Firm King Mattress 14 inch - Pain-Relieving Hybrid Mattress for Extra Lumbar & Hip Support - 365-Night Trial No Sagging Bed in a Box - No Odor, Fiberglass-Free, CertiPUR-US Certified
9.9Exceptional
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Value for Money2
MLILYEGOHOME 14 Inch King Size Memory Foam Mattress for Back Pain, Cooling Copper Gel Bed in a Box, Foam Made in USA, CertiPUR-US Certified, Therapeutic Medium Firm, 76x80x14 Black
14% OffKey specs-
size:King
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construction:High density base foam
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fill material:Memory foam
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dimensions:80 x 76 x 14 inches
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top style:Cooper gel aerofuion
9.8Exceptional
Our Rating
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3
![ZINUS 12 Inch Green Tea Memory Foam Mattress [New Version], King, Fiberglass free, Medium Firm Feel, Zoned Pressure Relief, Certified Safe Foams & Fabric, Mattress in A Box](https://d1ttb1lnpo2lvz.cloudfront.net/7e0a079/loader.svg)
ZINUSZINUS 12 Inch Green Tea Memory Foam Mattress [New Version], King, Fiberglass free, Medium Firm Feel, Zoned Pressure Relief, Certified Safe Foams & Fabric, Mattress in A Box
Key specs-
size:King
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construction:Zoned pressure relief
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fill material:Memory Foam
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dimensions:80 x 76 x 12 inches
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top style:N/A
9.7Exceptional
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4
EEN EEN SLEEPKing Size Mattress [Upgraded Strengthen] 14 Inch Firm King Mattress In A Box, Hybrid Mattresses With Gel Memory Foam & Independent Pocket Springs,Pressure Relief, Strong Edge Support,366-Night Trial
9.6Exceptional
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5
AyeawoAyeawo King Size Mattress 12 Inch,Firm King Mattress in a Box with Gel Memory Foam and Pocket Springs, Hybrid Mattresses Pressure Relief&Cooling Feel&Motion Isolation
25% Off9.5Excellent
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AyeawoAyeawo Firm King Size Mattress, 12 Inch Hybird King Bed Mattress with Gel Memory Foam and Pocket Springs, Comfort Bed in a Box, Pressure Relief and Motion Isolation, 365-Night Trial, CertiPUR-US
23% Off9.2Excellent
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7
AvencoAvenco King Mattress, 12 Inch Medium Firm King Size Mattress in a Box, Hybrid Mattresses with Smarts™ Coil Pocket Springs for Motion Isolation, Strong Edge Support, CertiPUR-US Certified
16% Off9.0Excellent
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8
LETMOONLETMOON King Mattress, 14 Inch Hybrid King Size Mattress in a Box, Medium Firm Memory Foam and Pocket Springs, Strong Edge Support, Pressure Relief
8.9Very Good
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9
LynnberyLynnbery 14 Inch King Size Mattress in a Box, Hybrid Cooling Gel Memory Foam & Pocketed Coils, Medium Firm, CertiPUR-US Certified, Pressure Relief, Motion Isolation
Key specs-
size:King
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construction:Hybrid
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fill material:Memory Foam
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dimensions:76L x 80W x 14Th
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top style:Tight Top
8.8Very Good
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10
RuoysunRuoysun 14 Inch King Size Mattress in a Box, Cooling& Breathable Firm Mattress with Gel Memory Foam and Pocket Springs for King Size Bed, Motion Isolation, 100 Night Sleep Trial, CertiPUR-US Certified
33% Off8.7Very Good
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