10 Year Warranty

New for 2017, the Comfortec Shelton Firm mattress is much more affordable than the bed-in-a-box options out there and offers the kind of sturdiness and great craftsmanship of the beds from long ago. Heavy duty foam encasment, dense foam layers and a company that produces its own foam are all contributing reasons why. The All-Natural Cotton Cover is an added plus. Don't let the low price tag fool you; the Shelton Firm is a very nice mattress.

The trademarked coil system ("Spectrum" by Symbol) is said to be significantly stronger than the ever-popular Pocketed Coil units out there and, it still contours to the individual sleeping on it very well.  This particular unit also offers 30% more springs in the middle-third of the mattress for strength and support where you need it most - in your lumbar region. An Insulator Pad helps to keep foam layers from dipping into the springs, over time. A Convoluted Extra Firm R65 layer provides not only support but breathability within the mattress; because, no one likes a hot sleep.

A great value and surely destined to become one of our best sellers, this is a great traditional-feel firm mattress that is 100% Made in the USA.

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Shelton Firm Mattress

This mattress can only be made in standard sizes. To see prices, please click here

Mattress Scale
semi firm mattress
Approx. Height of Mattress: 10"

This Mattress Features:

CertiPUR-US certified foams are:


✓ Made without ozone depleters
✓ Made without PBDEs, TDCPP or TCEP (”Tris”) flame retardants
✓ Made without mercury, lead, and other heavy metals
✓ Made without formaldehyde
✓ Low VOC (Volatile Organic Compound) emissions for indoor air quality (less than 0.5 parts per million)
✓ Made without phthalates regulated by the Consumer Product Safety Commission


Natural Cotton Cover
FR Fiber Barrier
Symbol Foam

Mattress(Top Side)
Symbol Foam
Convoluted Extra Firm R65 Foam
Insulator Pad

540-Spectrum Tri-Zoned Coil Unit, Foam Encased
Symbol Support Core


10 Total Years (10 full)

Shelton Firm Mattress

The Comfortec Shelton Firm is one of the latest offerings from Symbol Mattress. Its "Spectrum" coil unit is designed to surpass other coil units in terms of durability. In addition to the springs' increased strength, the "540 Spectrum Tri-Zoned" also contours to the body a considerable amount. Despite this mattress having some of the most advanced features in the industry, it's a very affordable model. This we definitely like!

Even Symbol's foams are manufactured in the United States; not imported like the foams used by nearly every other maker of mattresses. Another indicator of quality craftsmanship is the sheer weight of this mattress. While not immovable and not overly massy, for a ten inch thick mattress - the Shelton Firm has a healthy amount of weight to it. This is undoubtedly due to its 13.75 gauge steel coils and its 4" thick high density foam encasement.

For a firmer sleeping surface that's not quite as hard as the floor (though, we carry one that hard) but that is great for both back and stomach sleepers, the Shelton Firm may be the right mattress for you! Also available in custom sizes for RVs, boats, antique beds and more.



  • Shipping or delivery of this item to most areas within the 48 contiguous states only. Delivery of this item to Alaska, Hawaii, US Territories or APO/FPO addresses will require added charges. Please call customer service for rates and availability.
  • Free LTL freight delivery to most cities in the continental US. Destination must be accessible by large truck. Some locations may have a small surcharge.
  • LTL freight service is curbside to your driveway only. White Glove is available for an extra fee.
  • For complete details, read our Shipping and Return policies.



Measure all 4 sides of your mattress and bed frame before ordering.
We recommend you order the mattress 1 inch smaller than the space it is meant to fill. This will leave extra room for sheets, blankets, and variations in production size. Some people like a larger gap to really have room for your hands to reach down and change sheets easily. Please note that production size is not guaranteed to be exact. Most models are built within ±0.5 inches but the difference can be larger, especially on innerspring models. Custom mattresses are hand made by a factory worker who will take a standard mattress, then shorten it to your size. With the way spring coils are shaped, they will not work when cut in half, so an entire row of springs must be removed to modify mattress sizes. As each row is removed, the bed size changes by 1-2 inches, so your bed may not come exactly the size you order.

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Common Questions

What if it doesn't fit?
We will never ship out a mattress that exceeds the size you have ordered without contacting you first to check if the extra size will cause an issue. Since these are custom made for you they can not be returned, so please be careful when taking measurements. On some bed sets, the box spring will be a different size than the mattress so you will need to measure both pieces. Also, since beds are often set up not perfectly square, you will need to measure all four sides of the bed to find the correct size. Be sure to check for boards or bolts that might protrude in to the mattress area and order your pieces small enough to fit inside of these protrusions.
What sizes are available?
Any size is available upon request but with most models you are limited to being smaller than a King mattress. If you need an odd size bigger than a King, here are some models that can be supersized. Please call us to find out what prices would be.
Can I really order any size and shape?
At this time, with only 1 exception (found here), we only distribute 4-sided rectangular mattresses with no special notches cut from the corners. The size can be as large as a king, so up to 76" wide and up to 84" long. If you need an odd size bigger than a king, please call us to find out what models are available. You can also order a custom mattress small enough to fit in a baby's crib. Mattresses are formed by rows of metal springs and since springs cannot work if cut in half, your mattress core will be sized in 1-2 inch increments. This means that if you order 47x63 it will be built between 46x62 to 48x64 but most of the time it will come within 0.5 inches of the requested size. Please let us know how precise your size must be.
What about the box spring?
It is very important to measure the size of your box separate from your mattress because in many older bed sets, the box was made slightly smaller than the mattress. The length and width of solid foundation box springs can be custom made to fit exact dimensions. The thickness can not be customized but boxes are available in several standard thicknesses ranging from 4.5-9 inches.
How soon will my mattress arrive?
Once your order is paid for, a specialist from Michigan Discount Mattress will call you on the phone to verify your sizes and delivery information. Production will begin and usually takes 3-6 days. After production, the mattress will then be packaged at the warehouse within 48 hours to protect it during shipping to your home. Shipping takes 2-8 days depending on the destination city. The combination of producing, packing and delivering means that you should receive your mattress within 1-3 weeks of the day you order. Our streamlined process has successfully delivered 90% of our orders within 3 weeks.