Heavyweight Men's Wool Bottom Base Layer - 100% Merino Wool

Heavyweight Merino Warmth for Deep-Cold Adventures: The Men’s Wool Bottom Base Layer

When temperatures fall far enough that ordinary thermals aren't cutting it, the Katmai Heavyweight Men’s Wool Bottom Base Layer provides serious insulation without sacrificing the natural comfort of merino wool. Made from 100% Australian merino in a substantial 400 g/m² interlock knit, these thermal bottoms are designed for cold-weather hunting, winter camping, hiking, snowsports, and long days outside in freezing conditions.

Fine 18.5-micron fibers keep the heavyweight fabric comfortable against the skin, while a gusseted construction, flatlock seams, and ribbed ankle cuffs make the Katmai easy to wear beneath additional winter layers.

Thoughtful Design & Materials

100% Merino Wool: Made entirely from Australian merino wool for natural warmth, breathability, moisture management, and odor resistance.

Heavyweight Interlock Knit: The substantial 400 g/m² fabric provides significantly more insulation than lightweight and midweight base layers for serious cold-weather use.

Fine 18.5-Micron Fibers: Fine merino fibers create a soft next-to-skin feel despite the garment's heavyweight construction.

UPF 50+ Protection: The dense merino fabric provides substantial ultraviolet protection during exposed winter adventures.

Easy-Care Construction: Machine washable and tumble-dry compatible for practical care after long days outdoors.

Built for Serious Cold

Heavyweight Insulation: Designed for fall and winter conditions where maintaining body heat becomes a priority.

Deep-Cold Performance: Recommended for temperatures of 0°F and below during active use and approximately 0°F to 30°F during less active periods.

Natural Temperature Regulation: Merino wool helps retain warmth in cold conditions while allowing excess heat and moisture to escape when your activity level increases.

Insulates When Damp: Wool continues providing insulation when exposed to moisture, an important advantage during snowy conditions and high-output winter activities.

Designed for Comfortable Layering

Mid-Rise Waist: The waistband sits slightly below the belly button for comfortable coverage beneath additional layers.

Merino-Covered Waistband: Places soft merino wool against your skin instead of leaving elastic directly exposed.

Ribbed Ankle Cuffs: Help keep the legs securely positioned while pulling socks, boots, snow pants, or other layers over the top.

Regular Fit: Provides a standard fit with enough room for comfortable movement without becoming excessively loose beneath outerwear.

True-to-Size Design: Intended to provide the manufacturer's standard regular fit in your usual size.

Made to Move Outdoors

Gusseted Construction: Reduces stress through the crotch while providing greater freedom of movement for hiking, climbing, skiing, and other active pursuits.

Flatlock Seams: Smooth seams help minimize rubbing and chafing during extended activity.

Base-Layer Design: Wear directly against the skin beneath insulating pants, hunting gear, ski clothing, or weather-resistant outer layers.

Soft Next-to-Skin Feel: Fine merino fibers make the Katmai comfortable enough for extended wear during long winter days and overnight adventures.

Natural Merino Performance

Moisture Management: Merino fibers absorb moisture vapor from your skin and release it into the surrounding air, helping manage the environment inside your layering system.

Naturally Odor Resistant: Merino wool helps resist odor-causing bacteria, a valuable advantage for hunters, backpackers, and anyone wearing the same base layers for multiple days.

Breathable Warmth: Despite its substantial insulation, merino remains naturally breathable to help prevent excessive heat and moisture buildup.

Multi-Day Performance: The combination of warmth, moisture management, and natural odor resistance makes the Katmai particularly useful for extended cold-weather trips.

Product Details

• Product Type: Men’s Heavyweight Merino Wool Base Layer Bottom

• Fiber Content: 100% Merino Wool

• Wool Source: Australia

• Knit: 400 g/m² Heavyweight Interlock

• Fiber Diameter: 18.5 Microns

• UPF Rating: 50+

• Rise: Mid Rise

• Waistband: Merino Covered

• Gusset: Yes

• Ankle Cuffs: Ribbed

• Seams: Flatlock

• Layer Type: Base Layer

• Fit: Regular

• Sizing: Runs True to Size

• Weight: 14.4 oz / 408 g, Size Large

• Style #: 709

• Imported

Best Suited For

• Winter camping

• Cold-weather hiking

• Hunting

• Backpacking

• Skiing and snowboarding

• Ice fishing

• Snowsports

• Cold-weather outdoor work

• Everyday winter wear

• Deep-cold layering systems

Temperature Recommendations

• Active Use: Approximately 0°F and below

• Inactive Use: Approximately 0°F to 30°F

Actual comfort will vary depending on activity level, additional layers, wind, weather conditions, and individual temperature tolerance.

Care Instructions

• Turn inside out before washing

• Machine wash cold on gentle cycle with like colors

• Use mild or wool-specific detergent

• Tumble dry on low heat

• Do not use fabric softener

• Do not use bleach

• Store in an airtight container during extended periods of non-use

A Serious Base Layer for Serious Winter Conditions

The Katmai Heavyweight Men’s Wool Bottom Base Layer is built for the days when staying warm requires more than an ordinary pair of long johns. Its dense 400 g/m² merino construction provides substantial insulation while still offering the breathability, moisture management, and natural odor resistance that make wool so valuable outdoors. Comfortable enough to wear all day and warm enough for deep-winter conditions, the Katmai creates a dependable foundation for your coldest adventures.