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A man wearing a black 100 percent merino wool athletic quarter zip shown from the waist up against a solid white background.
  • A man wearing a black 100 percent merino wool athletic quarter zip shown from the waist up against a solid white background.
  • A man wearing a navy blue 100 percent merino wool athletic quarter zip shown from the back against a solid white background.
  • A man wearing a navy blue 100 percent merino wool athletic quarter zip with the collar unzipped shown from the waist up against a solid white background.
  • A man wearing a black 100 percent merino wool athletic quarter zip shown from the side against a solid white background.
  • A man wearing a black 100 percent merino wool athletic quarter zip with hands on hips shown at an angle against a solid white background.
  • A man wearing a black 100 percent merino wool athletic quarter zip adjusting the collar while looking out a window at a snowy landscape.
  • A man wearing a black 100 percent merino wool athletic quarter zip shown from the waist up against a solid white background.
  • A man wearing a navy blue 100 percent merino wool athletic quarter zip shown from the back against a solid white background.
  • A man wearing a navy blue 100 percent merino wool athletic quarter zip with the collar unzipped shown from the waist up against a solid white background.
  • A man wearing a black 100 percent merino wool athletic quarter zip shown from the side against a solid white background.
  • A man wearing a black 100 percent merino wool athletic quarter zip with hands on hips shown at an angle against a solid white background.
  • A man wearing a black 100 percent merino wool athletic quarter zip adjusting the collar while looking out a window at a snowy landscape.
100% Merino Wool Athletic Quarter Zip - Men's Heavyweight

100% Merino Wool Athletic Quarter Zip - Men's Heavyweight

$179.99
Color
Size

Built for sub-zero temps, howling winds, and heavy snowfall. Stay out longer with heavyweight thermal insulation and customizable ventilation when battling the elements.

Description

This 100 percent merino wool athletic quarter-zip, from the century-old Merino experts at Minus33 in New Hampshire, is dubbed the "Kobuk" after the Arctic national park in Alaska. It's an ultra-warm thermal layer cut from 400 GSM interlock knit fabric woven from Australian Merino wool. Featuring integrated thumbholes, a protective mock neck, and a semi-auto locking zipper for on-the-go venting, it delivers maximum comfort and protection in extreme winter conditions.

Materials

  • Fiber Content: 100% Merino Wool
  • Fabric Weight: 400 GSM Heavyweight
  • Knit Type: Interlock Knit
  • Fiber Fineness: 18.5 Micron Fibers
  • Sun Protection: UPF 50+
  • Certifications: OEKO-TEX® Standard 100, Woolmark®, Responsible Wool Standard® (RWS)
  • Care Rating: Total Easy Care (Machine Wash & Dry)

Construction & Fit

  • Total Garment Weight: 19.2 oz / 544g (Size Large)
  • Fit Type: Regular fit — standard cut with room to breathe without being baggy (Runs true to size)
  • Layer Type: Mid Layer, Insulating Layer
  • Neckline: 1/4 Zip Mock Neck
  • Hardware: YKK Semi-Auto Locking Zipper Pull with zipper garage
  • Cuffs: Integrated thumbholes for easy layering and added hand warmth
  • Stitching: Flatlock seams to prevent chafing
  • Label: Tagless design (no itchy neck tags)

Origin & Sourcing

  • Wool Source: 100% Australian Merino Wool
  • Ethical Standards: Responsible Wool Standard (RWS) certified animal welfare and land management

Recommended Uses

  • Ideal Seasons: Fall, Winter
  • Activities: Everyday Wear, Hiking, Camping, Biking, Running, Fishing, Hunting, Snowsports
  • Temperature Range: 0°F and below (Active) | 0°F to 30°F (Inactive)

Size Guide

Measurements refer to body size, not garment dimensions. All measurements are in inches.

Size Chest Waist Sleeve Length Shirt Length Inseam
XS 33–35" 24–27" 30–31" 25.5–26.5" 25–27"
S 35–38" 28–30" 31–32" 26.5–27.5" 28–30"
M 39–41" 31–33" 32–33" 27.5–28.5" 29–32"
L 42–45" 34–36" 33–34" 28.5–29.5" 32–34"
XL 46–48" 37–40" 34–35" 29.5–30.5" 32–35"
XXL 49–52" 41–44" 35–36" 30.5–31.5" 34–35"
XXXL 52–54" 45–49" 36–37" 31.5–32.5" 34–36"
Care Guide: Turn inside out before washing. Machine wash cold on a gentle cycle with like colors using mild or wool-specific detergent. Tumble dry low heat. Do NOT use fabric softener or bleach. For seasonal storage, place in an airtight container.

About Minus33

Rooted in over a century of New Hampshire woolen heritage, Minus33 designs performance-driven Merino wool apparel built for the elements. Born and tested in the rugged White Mountains, the brand focuses on natural fiber performance, thermal comfort, and durable construction for demanding outdoor pursuits.

Product Story

Kobuk [koe-book]: Kobuk Valley is home to a vast National Park, majestic sand dunes, 500,000 migrating caribou, and the life-giving Kobuk River. Located entirely within the Arctic Circle where winter night temperatures drop to -50°F, its roadless wilderness demands gear that offers uncompromising warmth and resilience.

Why No Polyester or Synthetic Blends

Your Kobuk Quarter Zip is crafted from 100% natural Merino wool and contains zero synthetic poly blends. Here's why that matters to your health.
Shipping & Returns Policy

Free Shipping: Shipping is free on all orders.

Return Policy: ShirtCastle Originals: Because each ShirtCastle Original is made to order, we're unable to accept returns or exchanges. Please review product details carefully before ordering.

For partner-brand products, contact us at aaron@shirtcastle.com to request a return.

Damages & Defects: In the rare event of a manufacturing error, we will replace your item for free—you do not need to ship the original back. To report an issue, email aaron@shirtcastle.com within 30 days of delivery and attach a clear photo of the defect. We will reply via email and process your replacement.

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