250 GSM is our everyday cold-weather standard — warm enough for winter city days, breathable enough for the trail.
Fabric weight guide
Which merino weight is right for you?
GSM is grams per square metre — how much fabric there is, not a warmth rating. Every weight is the same soft 17.5-micron Australian merino: it wicks sweat before it turns cold, insulates when it is cold and ventilates when it is warm. Lighter fabric breathes and dries faster; heavier fabric holds more heat when you stop moving. Choose by season and by how hard you will be working.
Warm & hot weather · 60°F+ / 15°C+ — and high effort in any season
Best for: summer hiking, running, cycling, hot-climate travel, everyday tees and office wear; the next-to-skin layer under a 250 when you work hard in winter
Pick this if: you want a shirt that stays fresh for days, dries in an hour and keeps you cooler than cotton in the heat — or you simply run hot
Think twice if: you will mostly be standing still in the cold; on its own a lightweight layer has little insulation to offer
Cool to mild · 40–65°F / 5–18°C
Best for: spring and fall as a standalone top, summer evenings, cool-morning hikes and commutes; winter as a base under a mid-layer
Pick this if: you want one merino layer that covers most of the year, or you are unsure between light and mid — this is where most people should start
Think twice if: you run cold and your winter is genuinely cold: go straight to 250
Cold · 20–45°F / −7–7°C — the classic winter base layer
Best for: skiing and snowboarding, winter hiking, cold-weather work, frosty fall mornings; top-and-bottom sets so your legs are not the weak link
Pick this if: you run cold in fall, want the classic winter base layer, or spend active days below freezing under a shell
Think twice if: you overheat easily on hard uphill efforts — a 165 or 190 underneath, 250 over it, is the better system
Deep cold · below 25°F / −4°C — especially when you stop moving
Best for: ice fishing, hunting stands, camp at altitude, winter mornings spent waiting rather than walking, a house that never quite gets warm
Pick this if: warmth matters more than breathability, you are chronically cold, or your winter involves long spells standing still outdoors
Think twice if: you will be working hard — it is too warm for a sweaty climb, which is exactly the point
A base layer works by sitting close to the skin, where it can move moisture — loose is not more comfortable, just slower. Between sizes? Size down for a next-to-skin layer under a shell, size up to wear it on its own or over another layer. Merino stretches with wear and springs back after a wash. Heavier weight is not itchier: itch comes from coarse fibre, and every weight here is the same superfine merino.
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Features & Details
Details:
Knit: 250 g/m2 Midweight
Layer Type: Base Layer, Mid Layer
Temperature Recommendations: 30°F to 0°F while active, 30°F to 60°F while inactive
Fit Type:
Regular - A standard fit that strikes the perfect balance between comfort and a tailored look, allowing for easy movement without feeling too loose.
Recommended Activities:
Everyday Wear, Hiking, Camping, Biking, Running, Fishing, Hunting, Snowsports
Description
Men's Merino Wool Thermal Set
This soft Men’s Merino Wool Thermal Set is designed for men who want warmth without irritation. Premium merino wool naturally regulates temperature and helps maintain comfort throughout changing weather conditions. Moisture-wicking fibers quickly remove sweat to prevent dampness and discomfort during long wear. Breathable fabric improves airflow, while natural odor resistance helps the set remain fresh after repeated use. The hypoallergenic texture feels smooth against the skin and eliminates the itchiness commonly associated with traditional wool.
Lightweight stretch construction supports flexibility and layering comfort. Anti-static performance, UV protection, and eco-friendly renewable wool fibers make this thermal set ideal for daily use.
Materials & Care
Washing and Drying Instructions
- Turn Inside Out
- Machine Wash Cold: Gentle cycle with like colors
- Detergent: Mild or wool-specific
- Lay flat to dry
- Storage: Wash before storage and keep in a dry place, using airtight containers or vacuum-sealed bag to prevent moth.
- Do NOT Use: Fabric softener or bleach!
Guarantee
- 30 Day Satisfaction Guarantee - Return Policy
- 1 Year Warranty
Merino.Tech - MIDWEIGHT 100% Merino
ULTRA COMFORT & INCREDIBLY WARM
Adaptable and cozy, our Merino Wool is your reliable companion. Crafted for three-season use, our Midweight functions seamlessly as both a base and mid layer.
NATURE'S WONDER TEXTILE
Thanks to the unique properties of Merino wool fibers, moisture is effectively drawn away from your skin, ensuring optimal comfort and moisture control. The intricate structure of Merino wool securely traps odor molecules, releasing them only during washing. This distinctive feature ensures that Merino wool remains resistant to the unpleasant odors commonly associated with alternative fibers.
THE FABRIC
01Fit Type:
Regular - A standard fit that strikes the perfect balance between comfort and a tailored look, allowing for easy movement without feeling too loose.
02Recommended Activities:
Everyday Wear, Hiking, Camping, Biking, Running, Fishing, Hunting, Snowsports
03Details:
Knit: 250 g/m2 Midweight
Layer Type: Base Layer, Mid Layer
Temperature Recommendations: 30°F to 0°F while active, 30°F to 60°F while inactive
Questions people ask about merino
What is merino wool, and what makes it different from regular wool?
Merino wool comes from Merino sheep and is measured in microns — the thickness of a single fibre. Merino.tech uses 17.5 micron Australian merino, which is roughly a third the thickness of the coarse wool most people remember from old jumpers. Finer fibres bend against the skin instead of pressing into it, which is why merino feels soft rather than scratchy while still insulating, breathing and resisting odour naturally.
Is merino wool itchy?
No. Itch is caused by fibre diameter, not by wool itself. Fibres above roughly 22 microns are stiff enough to trigger the prickle response; ours measure 17.5 microns, well under that threshold. Every piece here is 100% Australian merino with no synthetic blend in the body fabric, so there is nothing rough sitting against your skin.
How do I wash merino wool without ruining it?
Turn the garment inside out, machine wash cold on a gentle cycle with like colours, and use a mild or wool-specific detergent. Lay it flat to dry. Never use fabric softener or bleach — softener coats the fibre and destroys the breathability you paid for. Merino resists odour, so you can wear it several times between washes, which is the easiest way to make it last.
What weight should I choose for a base layer set?
250 GSM is the answer for most people — it carries from the first frost through midwinter and works while moving or sitting still. Choose 165 if you run hot or plan high-output activity, and 320 if you are outdoors in deep cold without much movement. A set gives you the matched top and bottom in one weight, which is simpler than mixing.
Does merino wool shrink?
It can, but only under heat and agitation. Hot water and a tumble dryer cause the scales on the fibre to lock together permanently. Cold water, a gentle cycle and flat drying prevent it entirely. Follow that and the garment keeps its shape for years.

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