Merino wool

Soft to silky texture
The finest types of Merino wool (SUPER FINE) have fibers with a diameter of 16 micrometers (microns), i.e. 0.016 millimeters. For comparison: a human hair is 100 micrometers in diameter.

Thermoregulation
Woolen textile materials create a microclimate on the body that prevents the rapid penetration of the external climate to the skin - whether cold in winter (wool "warms") or hot in summer (wool "cools").

Moisture wicking
The surface of the fiber is hydrophobic, therefore it repels sweat. Sweat either evaporates or, if retained (for example, by another layer of clothing), it soaks inside the fiber, which, in turn, is hydrophilic. The inside of the wool fiber has the ability to absorb moisture up to 30% of its weight without the fiber feeling damp or cold. Even a fully soaked fiber remains dry to the touch and at the same time does not lose any of its thermoregulatory ability.

Permeability
Wool textile material is very breathable even in a dense structure, This property also allows moisture in the fibers to evaporate quickly. Breathability is provided by the irregular surface structure of the woolen fiber, which is formed by microscopic scales.

Naturally Antibacterial
Wool is made up of 90% protein (keratin), binds harmful substances, including viruses and bacteria, limits their decomposition and multiplication. Woolen clothing does not smell even after multiple use. Alternatively, it is enough to ventilate the woolen clothing, which will get rid of any odors itself.

Wool is an anti-allergen
There are no known allergic reactions to wool (beware not to be confused with the so-called "allergy" to wool when people with sensitive skin feel uncomfortable when wearing ordinary wool, which has a large diameter in microns). Merino wool extra fine, or super fine (with 16 micrometers) has a delicate almost silky touch that does not bother even hardened opponents of wool.

Wool protects against UV radiation
Which many synthetic fibers do not do at all or only insufficiently.

Hollow fiber
Sheep wool is a natural hollow fiber.