Minus33 Katmai Men’s Expedition Weight Bottoms

With thick 400-GSM fabric, the Katmai Men’s Expedition Merino Bottoms from Minus33 are a must-own for winter explorers and adventurers.


You need to be protected if you are exploring nature in freezing temperatures, especially for extended periods. The Minus 33 Katmai Expedition Weight Bottoms should be your go-to long underwear for frigid winter activities.

These base layer bottoms sit just below the belly button. Furthermore, the fit is snug yet barely feel noticeable. The Merino-covered waistband and ankle cuffs hold firm. Thus, preventing rubbing and movement when worn as a base layer. Also, flatlock seams and gusseted crotch reduce chafing in sensitive areas. They were designed with your comfort in mind.

In other words, they feel like an extra protective layer of skin. It sounds strange, but it’s true.

Meanwhile, the 400-GSM fabric offers exceptional insulative properties yet is still breathable. The 18.5-micron fabric feels soft, making it an excellent protective layer.

Are you planning an expedition into the frigid wilderness? If so, bring along the protection and comfort of these Minus33 Katmai Men’s Expedition long underwear.

View Minus33 Sizing Charts & Company Profile

Katmai Expedition Specs & Features:

  • 100% Merino wool imported from Australia
  • Interlocking-knit, 400 GSM fabric weight
  • 18.5-micron fiber diameter
  • Slim-to-classic bottoms fit (tapered, as well)
  • UPF Rating 50+
  • Weight: 14.4 oz (size: large)
  • Only available in black


  • Quite possibly the warmest pair of base layer bottoms/long underwear on the market.
  • Super-soft, next-to-skin comfort perfect for winter activities.
  • All things considered, the heavier fabric density is still breathable.


  • User-reported issues with fit. Consult Minus33 sizing charts or contact Minus33 directly.
  • As a result of heavier fabric, they cost a bit more than other brands.

Best For:

Winter Sports

Featured In:

10 Best Long Underwear For Skiing

Additional Information about Minus33 Katmai Men’s Expedition Wool Bottoms:

Disclaimer: Merino Wool Gear DOES NOT sponsor products. Yet as an Amazon Associate, we may earn a commission from qualifying purchases.

Additional information

Merino Percentage

>95% Merino Wool

Fabric Density (gsm)

> 270 Heavyweight

Fiber Thickness (microns)



Semi-Fitted / Slim, Classic Fit / Regular


Winter Sports

Colors Available