Mil Spec & Marine Spec Waterproof Breathable Fabrics

Choosing the right outerwear fabric directly impacts your safety, comfort, and performance in marine environments. From offshore exposure to inshore mobility, each Mustang Survival fabric is engineered to balance waterproofness, breathability, and durability for specific conditions. This guide breaks down the differences between Mil Spec versus Marine Spec fabrics, as well as the differences within the Mil Spec fabric collection, so you can confidently select the right level of protection for your environment. 

 

Mustang Survival has over 60 years of experience building apparel for demanding marine conditions. We keep everyone dry, protected, and comfortable on the water through a careful and deliberate material selection, design, and construction process.   

We work with materials industry leaders to select samples specifically for each new product and its intended use. Then they are submitted to structural and environmental tests—waterproofness, breathability, resistance to oils (diesel, fish, etc.,) durability, and feel—to evaluate their performance in the harshest expected situations to ensure they meet our exceptionally high standards.    

Our design team are experts on marine environments and know where water is most likely to enter a garment; they work to minimize these exposed areas while still allowing the user a full range of movement. Our engineers obsess over the technical details that go into each of our products, including seam construction and leak and pressure tests in our in-house R&D and testing center, Waterlife Studio.   

This entire process culminates in marine apparel that optimizes the wearer's performance on the water.    

   

A Note About PFAS: In 2026, Mustang Survival began making Marine Spec materials without intentionally added PFAS. For our Mil Spec 6.5 GORE-TEX Fabric, we are following the phase-out process established by GORE-TEX. Visit our blog about PFAS to learn more.

  

Mil Spec 6.5 GORE-TEX  

We have been building leading dry solutions for military, coast guard, and water rescue professionals for decades. This expertise, military-grade fabrics, and a focus on maximizing waterproofness, breathability, and durability have allowed us to build the world's driest and toughest performance outerwear.   

Until 2017, only the military, Coast Guard, and public safety products used Mil Spec 6.5 GORE-TEX Fabric. The fabric features a 220-gsm weight, a highly durable 70D nylon face fabric resistant to punctures, abrasion, saltwater, and UV exposure, and a nylon tricot backer for added durability and next-to-skin comfort. With years of validation in the field, it is now available to recreational users who demand the highest level of protection in the harshest marine environments with our EP 6.5 Ocean collection.  

EXPLORE THE EP OCEAN COLLECTION

 

Marine Spec  

Intentionally developed for the rigours of marine use, Marine Spec is highly abrasion, UV, and saltwater resistant. The three levels of Marine Spec (BP, SP, and MP) have unique characteristics for different environments, exposure, and ocean-based activities.   

When choosing the Marine Spec fabric, we tested over 70 breathable materials and evaluated 12 different properties, totaling over 800 material tests, before completing real-world field assessments. The conclusion is Marine Spec is the ultimate combination of waterproofness, durability, and breathability.   

 

Marine Spec BP   

When the conditions and environment require nothing less than exceptional protection—rugged Marine Spec BP, the most puncture and abrasion-resistant fabric in the Marine Spec family, is the right choice. Modelled on Mil Spec 6.5 Gore-Tex, the Marine Spec BP demonstrates similar characteristics and performance.    

The 70D nylon face fabric is highly durable with abrasion, salt water and UV resistance. The internal bi-component membrane, hydrophilic PU membrane, and PFC-free hydrophobic PU coating provide the most breathable, waterproof, and windproof performance of the Marine Spec range and the nylon tricot backer offers next-to-skin comfort and extends the garment's life.    

With a weight of 195 gsm, the Marine Spec BP fabric keeps wearers comfortable and dry in Mustang Survival’s coastal and offshore apparel and dry suits. 

EXPLORE THE MARINE SPEC BP COLLECTION

 

  

Marine Spec SP  

Marine Spec SP is the most versatile fabric in the Marine Spec line. The 3-layer fabric system is waterproof and windproof with exceptional breathability and unparalleled protection. Using the same 70D nylon face fabric as in Marine Spec BP, it is abrasion, salt water and UV resistant. On the inside, the bi-component membrane—which is thinner than in the Marine Spec BP—with hydrophilic PU membrane and PFC-free hydrophobic PU coating is fully waterproof and windproof to keep out the elements while maintaining a high level of breathability. The nylon tricot backer protects the inner membrane and creates more comfort against the wearer's skin. At 180 gsm, it is lighter than Marine Spec BP. But, with the same laminated peel strength, pilling rating, 24-hour launder and tear strength, and similar abrasion and puncture resistance, this fabric makes limited concessions in performance.    

Select Mustang Survival inshore, and coastal apparel use Marine Spec SP.

EXPLORE THE MARINE SPEC SP COLLECTION

 

  

Marine Spec MP  

At 120 gsm, this is the lightest weight and most breathable fabric in the Marine Spec family; Marine Spec MP has a mechanical stretch that moves with its wearer and provides an unparalleled range of motion. The 3-layer construction is waterproof and windproof with a 50D nylon face fabric and inner monolithic and hydrophilic PU membranes. The nylon tricot backer is comfortable next to the skin and offers additional membrane protection. This fabric features a laminated peel with modest tear strength and puncture resistance, making it a great solution for transitioning through periodic inclement weather conditions.    

Our inshore apparel utilizes Marine Spec MP. 

EXPLORE THE MARINE SPEC MP COLLECTION

 

 

 

Waterproof Materials: Frequently Asked Questions 

Still have questions about our waterproof materials? We’ve answered some of the most common ones below. 

Is "Heavy-Duty" gear less breathable than lighter foul weather gear?  While thicker fabrics like Marine Spec BP and Mil Spec 6.5 have a higher GSM (weight), they utilize advanced bi-component membranes. These are specifically engineered to maintain high moisture vapor transfer, ensuring you stay dry from sweat even during high-output maneuvers in heavy seas.  

How does Marine Spec BP compare to Mil Spec 6.5 GORE-TEX?  Marine Spec BP was modeled directly after the performance characteristics of our Mil Spec 6.5 GORE-TEX. Both offer 70D nylon face fabrics for maximum abrasion and puncture resistance. The primary difference lies in the specific membrane technology and the rigorous military-specific testing protocols required for the 6.5 GORE-TEX line.  

Why is "Oil and Fuel Resistance" important for waterproof fabrics?  Standard waterproof membranes can be compromised or "contaminated" when exposed to diesel, oil, or even fish proteins, leading to delamination (peeling). Mustang Survival’s Marine Spec fabrics are tested to resist these common marine contaminants, ensuring the waterproof integrity remains intact in industrial and commercial environments.  

What is the benefit of a "Tricot Backer" in heavy-duty apparel?  The tricot backer is a fundamental feature in waterproof outerwear. It acts as a protective internal shield for the waterproof membrane, preventing damage from internal friction and body oils while providing a more comfortable, non-clammy feel against the skin.  

How does UV resistance affect the lifespan of my offshore gear?  Saltwater and constant sun exposure are the primary causes of fabric breakdown. Our high-denier nylon face fabrics are treated for UV resistance to prevent the fibers from becoming brittle or "bleaching," which maintains the garment’s tear strength and waterproofness over multiple seasons of use.  

When should I choose Marine Spec MP over the heavier BP or SP versions?  Marine Spec MP is engineered for lightweight protection without reducing mobility. If your activity requires a high range of motion—such as inshore racing or fast-paced deck work—the mechanical stretch and 120-gsm weight provide unparalleled mobility while still offering a 3-layer waterproof defense against periodic spray and rain.