100% Merino Wool

midweight 100% merino wool winter clothing skiing snowshoeing hunting base layers



We believe that wool is one of the best fibers in the world, so we strive to bring you products made with as much wool as possible so you can reap all the benefits of its all-natural advantages on your outdoor adventures.

Our 100% Wool collection is made from superfine, soft merino wool so you can be 100% Prepared for anything.

100% Merino Wool Weights

We currently offer the below weight options in 100% Merino Wool. For more details on selecting a weight for a specific activity, please visit our Fabric Weights Overview Page.

man sitting on rock wearing merino wool lightweight t-shirt



17.5 Microns

Jersey Knit

woman getting ready to go skiing zipping up merino wool midweight quarter zip



18.5 Microns

Interlock Knit

man hunting wearing minus33 merino wool expedition mid layer



18.5 Microns

Interlock Knit


Wilderness Expedition

Our Wilderness Expedition collection also features the benefits of 100% Merino Wool. Using a Ponte de Roma knit, it's twice as durable for twice the adventure.

What Does GSM Mean?

GSM (or g/m2) stands for Grams per Square Meter. It measures the weight of the fabric if you cut a 1x1 meter square of the fabric, and weighed it in grams. GSM is a good benchmark of the fabric's density, but not necessarily its thickness. This is because different fibers have different properties, and the way the fabric is knit or woven can also affect its thickness.

For wool, it is known for having a higher warmth-to-weight ratio. This is why a 235gsm merino wool shirt is much warmer than a similar GSM of cotton or synthetic fibers, even though they may feel similar in thickness to the touch. Our merino wool weights range from 145-400gsm, so you have a variety of options for all types of outdoor activities. Wool is a favorite among the outdoor community because its high warmth-to-weight ratio means that you can carry a product that packs a punch, while saving valuable space in your pack.

Understanding Microns

Wool’s softness is determined by the micron gauge of the individual fibers. The micron is essentially the diameter of the fiber. The lower the micron, the softer the wool.

Minus33 uses Superfine 18.5 micron Merino Wool for our Midweight and Expedition products, and Ultrafine 17.5 micron for our Lightweight and Micro products. This gauge of wool provides just the right balance of durability and a super soft feel on the skin.


Extra Ultrafine: 16.0 and below
Ultrafine: 16.1-17.5
Superfine: 17.6-18.5
Fine: 18.6-19.5
Fine Medium: 19.6-20.5
Medium: 20.6-22.5*
Strong: 22.6 and above

*Wool will start to feel itchier around 21 microns.

To put it in perspective, the typical human hair is around 60 microns.

Types of Knits

The 2 knit types within our 100% Merino Wool collection are Jersey Knit and Interlock Knit. 

Jersey Knit is a single layer with soft stretch. Jersey is ideal for close-fitting garments because it stretches to move with you. It's also absorbent and breathable.

Interlock Knit is a variation of a rib knit. It has two rows of stitches with one behind the other, giving it the texture of a double-knit fabric (technically they are one). Interlock knit has great durability, stretch, and drape, which is perfect for both base and mid-layers.