Lightweight Next-to-Skin Performance
Build your day on a solid foundation with the K1 - Primus Long John baselayer. Wool balanced with synthetic fibers delivers long-lasting durability, simple wash cycles, and the fast moisture transport your layering system needs. Flat seams ensure bulk-free layering, and a specialized fly provides support and fuss-free access (even with gloves).
Beyond Wool
Our wool combines with synthetic fibers to create the ideal performance fusion for moisture management: wicking up and lifting out sweat, protecting against odors and wash shrinkage, increasing durability, and ensuring next-to-skin comfort. Your system’s moisture transport starts here.

Package Deal
The Ballhalla™ fly keeps you comfortable all day long with anatomical support and minimal bulk, and the unique design ensures easy access even while wearing gloves.

Fuss-Free Foundation
Flat-seam construction ensures all-day comfort, delivering a smooth next-to-skin feel and reducing bulk when layering up.

K1 - PRIMUS
USE GUIDE
WHEN TO USE
Below 50° F as a next-to-skin baselayer.
PAIRS GREAT WITH
Active insulation and softshells.
BENEFIT OVER OTHER LAYERS
Highly breathable, fast-drying layer that can have any other layer worn over it.
Learn more about layering:
VIEW SYSTEM BUILDERSPECS
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Layer Level1
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Body Material2.7 oz. piqué 78% polyester/27% wool
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Weight (Size L)7.1 oz.
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Wind ResistantNo
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BreathableYes
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Moisture WickingYes
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Fast DryingYes
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PocketsNone
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SourceImported

Trade Agreements Act Compliant
Designed in Seattle. Imported.
Need Help? Contact us with any size or fit questions. 206-767-0307
Primus K1 Long JohnSizing Information
Height 5' 8" - 6' 2"
Short: -2 Inches Inseam
Long: +2 Inches Inseam
Size | Waist | Hip | Inseam Regular |
---|---|---|---|
S | 30-31 | 37-38 | 29 |
M | 33-34 | 40-41 | 30 |
L | 36-37 | 43-44 | 31 |
XL | 39-40 | 46-47 | 32 |
2XL | 42-43 | 49-50 | 32 |
3XL | 45-46 | 52-53 | 32 |
4XL | 48-49 | 55-56 | 32 |
Waist Preferred Pant Waist
Hip 7" Below Preferred Waist
Inseam Regular Crotch to floor
Fit Information
Standard True to Size | Active Layering
Expedition Oversized | Static Layering
Learn more about our layering systems
System Builder