Find Your Perfect Base Layer.
Discover NowSuper warm and cosy baselayer
"Great base layer in charcoal. Grey is a little sheer but fine if you wear with a bra underneath. Hugs all the right places."
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$90.99
$129.99
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Dernier prix $129.99 -
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$90.99
$129.99
This item's price has been updated recently to ensure you get the best value.
Dernier prix $129.99 -
-30% Off
A soft and stretchy women’s T-shirt for everyday comfort, the Merino 150 Siren Long Sleeve Sweetheart features our corespun fabric that’s naturally odour resistant and soft next to your skin.
Good for:

83% Merino Wool/ 12% Polyamide/ 5% Elastane Exclusive of decoration
Machine wash warm. Wash inside out with like colors. Do not use softeners. Fasten all closures to wash and dry. Do not bleach. Do not tumble dry. Line dry in shade. Warm iron. Do not iron print, trims and accessories. Do not dry clean.
Model measurements
Height: 179cm / 5'10". Waist: 62cm / 24". Anya is wearing size S.
Key product measurements
Height: 61.5cm (Based on size S); Width:41.5cm (bottom opening width, size S)
Regular Fit
Slim
The Siren is a lightweight next-to-skin layer. It’s crafted from 150gm merino jersey corespun fabric that’s lighter than most other fabrics we use, and is made with a snug, slim fit that works perfectly as a cosy piece beneath your other layers. Our Siren tees fit tighter than other tees in our range, just size up if you like a looser fit.
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Merino wool neutralizes unpleasant odors by absorbing odour molecules into its fibers, making them less detectable by the human nose.
Merino fibers efficiently manage moisture, absorbing it from your skin and releasing it into the atmosphere. It can absorb up to 35% of its weight in water without feeling wet.
icebreaker merino wool garments undergo special anti-shrinkage treatment, helping to resist deformation and pilling.
The thermo-regulation properties of merino wool adapt to your body and external conditions, so you can stay warm in the cold and cool in the heat.
Overall rating: 4.6013074 / 5 from 612 reviews.
This long sleeve T-shirt offers a slim fit and is made from a soft, stretchy merino wool blend fabric. Customers appreciate its high quality, versatile color options, and flattering neckline. It serves well as a base layer and fits comfortably for most people.
Review topics: ["fit","size","weight","length","weather","quality","fabric","problem","material","looks","wear","value","delivery","feel","comfort","colour","top","layer","neck","price","warmth","sleeves","style","shirt","winter","arms","stretch","works","medium","shape"].
"Great base layer in charcoal. Grey is a little sheer but fine if you wear with a bra underneath. Hugs all the right places."
— Mark (5/5)
"Nice top but I do not like it as much as I like the crew neck."
— LORIE R. (4/5)
"Perfect for base layering under sweaters with low or wide necklines. No visible logo/brand name, which I prefer."
— Alaina M. (5/5)
"Comfortable, snug, base layer. Very happy with it."
— Margaret R. (5/5)
"Perfect fit and weight"
— Julie G. (5/5)
"J'adore ce haut. J'en achète 2-3 par an et je les mets autant pour dormir qu'en couche de base. Chandail mince mais qui procure la petite chaleur nécessaire parfaite et qui se met bien sous n'importe quel pull. La coupe est très belle et flatteuse. Je recommande vivement!"
— Moi (5/5)
"Superbe!"
— Lisette L. (5/5)
"I was disappointed when this arrived and I realised that I had bought a non 100% wool product. However, I have worn and been won over as it has none of the drawbacks of other mixed products I have worn. Very comfortable and flattering fit. I would not buy a mixed product again (except by mistake) but I am very happy with this top."
— Jean (5/5)
"This is the first time that I brought an ice breaker product and I am very happy. I bought the heavier weight and this one, and I really like the neck line which is invisible undershirts. It is a very light layer and while it is warm, it's also discreet. You can tell the difference in heat between this and the 260 icebreaker."
— Rosinky (5/5)
"I love the neckline and figure hugging fit of this tee. I wear it alone but it would also work great as an undershirt during cooler months. The feel isn't as silky soft as some of my other Icebreaker clothing but I don't find it itchy at all."
— Lynnie (5/5)
Find the size that fits you best based on people just like you.
Use the chart below to determine your size. If you’re between two sizes, order the smaller size for a tighter fit or the larger size for a looser fit. If your measurements for chest and waist correspond to two different sizes, order the size indicated by your chest measurement for tops and your hip measurement for pants.
| XS | S | M | L | XL | |
|---|---|---|---|---|---|
| Bust | 30-32 | 32-34 | 34-37 | 37-40 | 40-42 |
| Arm length | 30.25-30.5 | 30.5-30.75 | 30.75-31 | 31-31.25 | 31.25-31.5 |
| Waist | 24-26 | 26-28 | 28-30 | 30-32 | 32-35 |
| Hips | 34-36 | 36-38 | 38-40 | 40-42 | 42-44 |
| XS | S | M | L | XL | |
|---|---|---|---|---|---|
| Bust | 76-82 | 82-88 | 88-94 | 94-100 | 100-107 |
| Arm length | 77-77.5 | 77.5-78 | 78-78.5 | 78.5-79 | 79-79.5 |
| Waist | 58-64 | 64-70 | 70-76 | 76-82 | 82-89 |
| Hips | 84-90 | 90-96 | 96-102 | 102-107 | 107-113 |
Our three different fits - slim, regular, and relaxed - ensure that when worn together, layers move and breathe like a single garment.
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