The Sierra 9" Semi Firm Mattress

Polysleep The Sierra Memory Foam Mattress - Semi Firm

Available in - Twin | Double | Queen | King

• Twin: 75"L x 39"W x 9"H
• Double: 75"L x 54"W x 9"H
• Queen: 80"L x 60"W x 9"H
• King: 80"L x 76"W x 9"H

Actual size may vary by model, generally within a range of ± 1 inch (2.5 cm)

Polysleep The Sierra Memory Foam Mattress - Semi Firm

Features:

• Mattress Type: Memory Foam with 2 Layers
• Removable cover: 100% Polyester
• Profile: 9" Thickness
• Suggested Firmness: Semi Firm
• Adjustable Bed Compatible: Yes
• Vented: Yes, Breathable Construction
• Comfort layer (2"): Open cell Viscoelastic Hybrid Foam
• Support layer (7"): Poly Foam Density of 1.5 lb
• Latex Free: Our Foams are Latex Free
• CertiPUR - US Certified
• ISO 20743: ISO certified medical standard
• Country of Origin: Canada
• Developed by certified Master Craftsmen
• Warranty: 5 Years Warranty

Firmness is subject to how the mattress feels to each individual, the feels described here are suggestions. The best way is to try a new mattress to see how the mattress feels to you. Please visit Masterbedroomstores for more information.

Overview

Sleep comes easier when comfort and support work together. The Sierra Mattress is built with breathable, pressure-relieving foams on a stable base, so your spine stays aligned while your body relaxes. The result is a cooler, quieter night with fewer wake ups.

Key benefits

• Cooling comfort that helps reduce heat build up through breathable, open-cell foams
  
• Pressure relief for shoulders and hips so muscles can let go
  
• Reliable support from a stable core that resists sagging
  
• Low motion transfer so partners move without disturbing each other
  
• Reinforced edges for secure sitting and a larger usable sleep surface
  
• Semi Firm feel tuned for side, back, and combination sleepers
  

Who it’s perfect for

• Side sleepers seeking cushioned pressure relief with proper alignment
  
• Back sleepers who want even support without a stiff feel
  
• Couples who value motion control and strong edge support
  
• Hot sleepers who prefer breathable materials and better airflow
  

Feel and firmness

Semi Firm, designed to balance contouring comfort with lifted support. You should feel gentle pressure relief at contact points while your mid-section stays lifted to help keep the spine neutral.

Construction and materials

• Cooling cover: soft knit that encourages airflow and wicks moisture
  
• Comfort layer: breathable, pressure-relieving foam that contours evenly
  
• Transition layer: responsive foam that reduces sink and smooths movement
  
• Support core: high-density base foam for stability and long-term shape
  
• Edge reinforcement: firmer perimeter feel for easier getting in and out of bed
  

Compatibility

Works with platform beds, solid foundations, slatted bases with close spacing, and adjustable bases. Ensure slats are sturdy and closely spaced for best support.

Setup and care

• Unbox, place on your foundation, remove wrap, and let the mattress expand.
  
• Allow a few hours for full expansion and ventilation.
  
• Rotate head to toe every few months to promote even wear.
  
• Spot clean the cover as needed with mild detergent. Avoid harsh chemicals.
  

Sizing guide

Available in standard sizes from Twin to King. Choose the size that matches your frame and room layout. For couples, Queen or larger is recommended for personal space and motion isolation.

Sleep benefits you can feel

• Easier alignment that helps reduce morning stiffness
  
• Calmer nights thanks to motion control and edge stability
  
• A fresher sleep surface supported by breathable materials
  

FAQs

What firmness is The Sierra Mattress

Semi Firm. It balances contouring comfort with supportive lift.

Will it sleep hot

The breathable cover and open-cell comfort foams are designed to help release heat and support airflow.

Is it good for couples

Yes. The design limits motion transfer and the reinforced edges create a more stable, roomy surface.

Which base should I use

A solid platform, closely spaced slats, or an adjustable base. Avoid worn-out box springs or widely spaced slats.