Ultimate Warm Base Layer & Thermal Bottoms | Seirus Innovation

Cold weather base layers are essential for warmth and comfort. Our Heatwave Technology amplifies and retains radiating warmth, maximizing your cold-weather comfort. From mountain peaks to city streets, this versatile innovation ensures you begin your journey feeling warm and remain that way all the way through.

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The Ultimate Warm Base Layer Tops & Bottoms

If you’re shopping for cold weather base layers, you came to the right place. We pour our hearts into our products to ensure our customers have the best outdoor experience.

What Seirus Is Known For:

Innovation: With a remarkable legacy dating to 1978, we've earned over 20 patents, highlighting our commitment to innovative outdoor gear. We consistently push boundaries by using the latest fabrics, advanced technologies, and a unique R&D process. This blend of innovation and dedication yields dependable, high-performance gear.

Quality:
Our products are celebrated for exceptional durability, a key element in crafting gear for a wide range of outdoor conditions, spanning freezing winters to scorching summers. We depend on real-life feedback from trusted partners and customers to ensure our gear consistently delivers comfort and protection.

Comfort: No matter the season, we all venture outdoors. Whether it's skiing, snowboarding, hunting, camping, fishing, or simply exploring nature, we're out there. Whatever draws you outdoors, staying warm and comfortable is key. Our gear is designed to envelop you in warmth and protection from head to toe. We're not talking about just enough warmth to tough it out, we're talking about seriously, pleasantly warm.

Integrity: We’re a dedicated team of co-creators committed to crafting practical outdoor solutions through hands-on research and development. Our approach is grounded in real-world functionality, always prioritizing solutions for genuine outdoor needs.

Trust in our commitment to excellence, and embark on your outdoor adventure with Seirus today!

Our Base Layers come in a variety of sizes and features, check out our Heatwave Body Mapped Base Layer, All Season Base Layer, or our Heatwave Winter Weight Base Layer. They’re a trusted choice — just see how much our customers love them!

If you have any questions as you browse the Seirus Innovation store, reach out to our customer care team.

Base Layer FAQs

Are base layers different than thermals?

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While thermals were initially coined as the original term for undergarments designed to provide warmth in cold weather, the concept has evolved over the years into what is now commonly referred to as base layers. While both thermals and base layers share common features, base layers have embraced a more versatile approach to outdoor comfort and warmth. Unlike traditional thermals, which were specifically tailored for cold weather and insulation, modern base layers are designed to be adaptable to various climates, accommodate diverse core body temperature needs, and cater to a range of activity intensities. This evolution has made base layers suitable for a wider array of unique requirements beyond their original cold-weather insulation purpose.

What Base Layers are great for extremely cold weather?

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Our Base Layers are made to withstand chilly to extremely cold weather, offering warmth, moisture-wicking, and insulation in a wide-range of environments. The Seirus Heatwave All Season base layer is a great choice for versatility as well as the Body-Mapped Performance Base Layer.

Should base layers be tight or loose?

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Base layers should fit snugly but not be overly tight. A close fit helps with insulation and moisture-wicking, ensuring optimal comfort and performance.

What cold weather base layers do I need?

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The number of base layer sets you need depends on several factors. With Seirus base layer sets, a single set often suffices, but it's wise to consider the climate, planned activity, and your core body temperature when deciding how many sets to have on hand. Colder temperatures require higher performance base layers, while specific activities demand varying levels of insulation and breathability. Additionally, individual cold sensitivity varies, with some people naturally generating more body heat than others.

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The Ultimate Warm Base Layer Tops & Bottoms

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BASE LAYER

Women's Heatwave™ Body Mapped Base Layer Long Sleeve 1-4 Zip Top

Women's Heatwave™ Body Mapped Base Layer Long Sleeve 1-4 Zip Top

Mens Heatwave™ Body Mapped Base Layer Long Sleeve Top

Mens Heatwave™ Body Mapped Base Layer Long Sleeve Top

Men's Heatwave™ Body Mapped Full Length Bottom

Men's Heatwave™ Body Mapped Full Length Bottom

Women's Heatwave Mapped Full Length Bottom

Women's Heatwave Mapped Full Length Bottom

Women's Heatwave™ Winter Weight Long Sleeve Crew Top

Women's Heatwave™ Winter Weight Long Sleeve Crew Top

Men's Heatwave™ Winter Weight Long Sleeve Crew Top

Men's Heatwave™ Winter Weight Long Sleeve Crew Top

Women's Heatwave™ Winter Weight Full Length Bottom

Women's Heatwave™ Winter Weight Full Length Bottom

Men's Heatwave™ Winter Weight Full Length Bottom

Men's Heatwave™ Winter Weight Full Length Bottom

Men's Heatwave™ All Season Full Length Bottom

Men's Heatwave™ All Season Full Length Bottom

Men's Heatwave™ All Season Long Sleeve Top

Men's Heatwave™ All Season Long Sleeve Top

Women's Heatwave™ All Season Long Sleeve Top

Women's Heatwave™ All Season Long Sleeve Top

Women's Heatwave™ All Season Full Length Bottom

Women's Heatwave™ All Season Full Length Bottom

Mens Heatwave™ Body Mapped Base Layer Long Sleeve ¼ Zip Mock Neck Top

Mens Heatwave™ Body Mapped Base Layer Long Sleeve ¼ Zip Mock Neck Top

Mens Heatwave™ Body Mapped Base Layer Quick Hoodie Top

Mens Heatwave™ Body Mapped Base Layer Quick Hoodie Top

Womens Heatwave™ Body Mapped Base Layer Long Sleeve ¼ Zip Mock Neck Top

Womens Heatwave™ Body Mapped Base Layer Long Sleeve ¼ Zip Mock Neck Top

Womens Heatwave™ Body Mapped Base Layer Quick Hoodie Top

Womens Heatwave™ Body Mapped Base Layer Quick Hoodie Top

The Ultimate Warm Base Layer Tops & Bottoms

Base Layer FAQs

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