Last Updated on March 23, 2026 by Rebecca Metz

Most mattresses look similar from the outside.

They have soft covers, plush quilting, and reassuring marketing language about comfort and support. But the materials that determine how a mattress performs are hidden inside layers most buyers never see.

There is one place where those materials must be listed: the law tag.

If you know how to read it, you can quickly see what is actually inside a mattress without relying on marketing claims.

This guide explains what a mattress law tag is, what the materials listed on it mean, and how to use it to compare mattress quality before you buy.

What Is a Mattress Law Tag?

A mattress law tag is a legally required label that lists the primary materials used inside a mattress. Every mattress sold in the United States must include one.

The tag typically lists:

• the materials inside the mattress
• the percentage of each material
• the manufacturer or importer
• the country of manufacture

The purpose of the law tag is consumer protection. It allows buyers to verify that a mattress contains the materials the manufacturer claims.

While marketing descriptions can be vague, the law tag must disclose the primary fill materials used inside the product.

Why the Label Says “Do Not Remove Under Penalty of Law”

That warning often sounds alarming, but it does not apply to the consumer. It applies to manufacturers and retailers before the mattress is sold.

Historically, some manufacturers advertised high-quality fillings while using cheaper materials inside. Law tag regulations were created to prevent that practice.

Once the mattress belongs to you, you are free to remove the tag. Many people leave it attached because it remains the easiest reference for the materials inside the mattress. It is also recommended to leave the law tag on in case you should need to process a warranty claim on the mattress in the future.

Where to Find the Law Tag

The law tag is usually sewn into the side seam of the mattress, near the head or foot. It is typically a white rectangular label and may include:

• fill material percentages
• manufacturer name
• registration numbers
• certification references
• country of manufacture

If you are comparing mattresses in a showroom, asking to see the law tag is one of the quickest ways to understand how the mattress is built.

How to Read the Materials on a Law Tag

Most materials listed on law tags fall into a few common categories. Understanding these terms makes it much easier to evaluate a mattress.

Polyurethane Foam

Polyurethane foam is the most common material used in modern mattresses.

It appears on law tags as:

• polyurethane foam
• flexible polyurethane foam
• viscoelastic foam (memory foam)

Foam can vary widely in quality. Lower-density foam tends to soften and break down faster than higher-density foam.

If a law tag lists a very high percentage of polyurethane foam, the mattress is largely synthetic foam.

Latex Foam

Latex foam is made from rubber tree sap or synthetic rubber.

On a law tag it may appear as:

• latex foam
• natural latex
• blended latex

Natural latex is known for durability, resilience, and temperature neutrality. Certified organic latex should carry the GOLS certification.

Cotton Fiber

Cotton is commonly used in mattress covers and quilting layers.

It may appear on a law tag as:

• cotton fiber
• organic cotton
• cotton batting

Cotton is breathable and comfortable but is usually part of a layered construction rather than the main support material.

Wool

Wool is frequently used in higher-quality mattresses as both a comfort layer and a natural fire barrier.

Wool resists ignition naturally and can help mattresses pass federal fire safety standards without chemical flame retardants.

On a law tag it may appear as:

• wool fiber
• wool batting
• organic wool

Polyester Fiber

Polyester is a synthetic fiber used in quilting layers.

It may appear on a law tag as:

• polyester fiber
• polyester batting
• synthetic fiber

Polyester adds loft and softness but is generally considered a lower-cost and lower-performing material compared with natural fibers.

Materials That Can Raise Questions

Some materials listed on law tags deserve closer attention. They do not automatically mean a mattress is unsafe, but they are worth understanding.

Fiberglass or Glass Fiber

Some mattresses use fiberglass as a fire barrier.

It may appear on a law tag as:

• fiberglass
• glass fiber
• glass wool

Fiberglass barriers are inexpensive and common in lower-cost foam mattresses. Many shoppers avoid them because if the barrier becomes exposed, the microscopic fibers can spread through fabrics and cause irritation.

Higher-quality mattresses typically use natural wool fire barriers instead.

“Inorganic Fiber”

This term sometimes describes mineral-based fire barrier fibers. It does not always mean fiberglass, but it is reasonable to ask the manufacturer what the specific material is.

Unspecified Foam

Some law tags simply list “foam.” This usually means polyurethane foam, which is the most common foam used in mattress manufacturing.

Example: Interpreting a Law Tag

Example law tag:

94% polyurethane foam

6% polyester fiber

This mattress is primarily synthetic foam and fiber.

A mattress focused on natural materials might list something like:

70% latex foam

20% cotton fiber

10% wool

The law tag gives you a much clearer picture of the product than marketing language alone.

Law Tag vs Certifications

A law tag and a certification serve different purposes.

Law Tag:  

Shows the materials inside the mattress.

Certifications:  

Verify how those materials were grown, processed, or tested.

Common certifications include:

• GOTS – organic textiles
• GOLS – organic latex
• GREENGUARD Gold – low chemical emissions
• MADE SAFE – ingredient safety screening

When a mattress carries these certifications, its materials and manufacturing process have been independently evaluated.

What You Will Find Inside Mattresses at Austin Natural Mattress

Austin Natural Mattress focuses exclusively on natural, organic, and non-toxic sleep products. This is not a category inside the store. It is the standard applied to every product in our showroom.

Mattresses that contain fiberglass fire barriers or chemical flame retardants are not carried.

Brands available include:

• Naturepedic
• Avocado Green Mattress
• Vispring
• The Natural Mattress Home
• Coyuchi
• Sleep & Beyond

Visit Austin Natural Mattress

If you want to see how mattresses are constructed and compare materials in person, the team at Austin Natural Mattress can walk you through the layers inside each product and explain how to read the law tag.

Austin Natural Mattress
7530 Burnet Rd
Austin, TX 78757
Phone: (512) 452-4444

Website: austinnaturalmattress.com

Store Hours
Monday – Friday: 10:00 AM – 7:00 PM
Saturday: 10:00 AM – 5:00 PM
Sunday: 12:00 PM – 6:00 PM

Frequently Asked Questions

What does a mattress law tag actually tell you?

A mattress law tag lists the primary materials used inside the mattress and the approximate percentage of each material. It helps consumers verify what fillings are used instead of relying only on marketing descriptions.

Does a mattress law tag list every material in the mattress?

No. Law tags usually list the main fill materials but may not include every glue, thread, or finish used in construction. Certifications and manufacturer documentation provide additional details about how materials are produced and tested.

How can I tell if a mattress contains fiberglass?

Check the law tag for terms such as fiberglass, glass fiber, or glass wool. If the wording is unclear, ask the retailer what material is used as the fire barrier. Mattresses that use wool fire barriers typically do not contain fiberglass. Another red flag is if you see a tag that warns against removing the outer cover of the mattress.