S3 Long Tights

S3 Long Tights are developed for running in the cold, wind, wet weather and sub-zero temperatures. They combine a protective 3-layer fabric on the front of the thighs and knees with a stretchier fabric on the back.

This is because your legs have different needs on winter runs. The front takes wind and wet weather head-on, while the back needs to follow your movement more and help your body manage heat and moisture.

The result is a pair of winter tights that combines weather protection, warmth and freedom of movement. S3 Long Tights are unisex and developed for both men and women.

The front of the thighs and knees uses a 3-layer fabric with a stretchy outer face, a membrane and a soft inner face.

The front fabric weighs around 290 g/m². The outer face is 73% polyamide and 27% elastane, while the inner face is 100% polyester. The back of the tights is 85% polyamide and 15% elastane.

This creates a zoned construction: more protection on the front and more flexibility on the back.

The front fabric is tested to a water column of at least 10,000 mm according to EN ISO 20811.

A water column test measures how much water pressure a fabric can withstand before water gets through. The higher the number, the greater the fabric's resistance to water pressure.

A minimum of 10,000 mm is a strong result for this type of winter fabric and documents high resistance to water passing through the front fabric itself.

In practice, this means your thighs and knees are well protected from rain and wet winter weather.

The water column rating applies to the front fabric, so it does not mean that the S3 Long Tights as a whole are constructed as a fully waterproof product with, for example, taped seams.

The front fabric has been tested for air permeability according to EN 9237 and measures a maximum of 5 mm of air per second.

The test measures how much air can pass through the fabric. A low figure means that relatively little air gets through.

The result shows very low air permeability, which makes it a strong result for a winter product where the front needs to protect against cold wind.

For you as a runner, this means the wind has a harder time getting straight through the fabric on your thighs and knees. It helps reduce the cooling effect of the wind on your legs.

The front fabric achieves a score of 100 in the spray test according to UNI EN 24920.

The spray test examines how well the surface of the fabric resists wetting when water hits it from the outside. 100 is the top score on the test scale.
That makes it a very strong result for surface water repellency.

For you as a runner, this means raindrops largely stay on the surface instead of quickly soaking into the fabric.

The spray test and the water column measure two different things:

The spray test tells you how well the surface repels water.
The water column tells you how much water pressure the fabric itself can withstand.

Together they give a more precise picture of how well the front fabric protects you in wet winter weather.

Yes. The front fabric's resistance to water vapour has been tested at Ret ≤18 m² Pa/W according to ISO 11092.

Ret tells you how difficult it is for water vapour to pass through the fabric. The lower the number, the more easily moisture in the form of water vapour can escape.

A Ret value of up to 18 shows that the fabric has a real ability to transport water vapour, while also being built to protect against wind and water. That is a sound result for a protective winter fabric, but it needs to be understood correctly: maximum ventilation is not the goal.

The front's first job is to protect you from cold and weather, while still letting some of the moisture your body produces when you run escape.

In practice, this means you can expect a protective front fabric that works well for running in cold, unsettled weather, but which will naturally feel more closed than a light, open running fabric.

That is why the back of the tights is made from a different, more elastic fabric, so the construction as a whole balances weather protection, freedom of movement and the management of heat and moisture.

The soft inside of the front fabric adds to the insulation and gives a cosier feel against your legs.

At the same time, the very low air permeability of the front fabric helps reduce the cooling effect of the wind.

This means the sense of warmth does not come from the thickness of the fabric alone. It also comes from less cold air being able to pass straight through the front.

For you, that means a more protected, cosier feel on cold runs.

Because maximum protection over the whole leg is not necessarily the best solution when you are actively running.

The front of the thighs and knees meets wind and rain head-on, so that is where the protective membrane construction is needed most.

The back of the legs needs more stretch, freedom of movement and the ability to manage heat and moisture.

It is therefore a deliberate zoned design: different fabrics are used where their properties add the most value.

The S3 Long Tights have a close-fitting unisex fit.

The wide waist elastic is combined with a built-in drawcord, so you can adjust the stability around the waist yourself.

A close fit matters on a winter product, because the fabrics need to work closely with the body and follow the legs through the running stride.

If you are usually between two sizes or prefer more room, you can choose the larger size.

Yes. The front fabric has been tested for abrasion according to EN ISO 12947-2 and withstands at least 20,000 Martindale cycles at 9 kPa.

The Martindale test subjects the fabric to repeated mechanical friction.

20,000 cycles documents that the fabric shows solid resistance to wear in the test. That is a relevant result for a winter product that has to cope with many hours of training, repeated movement and regular washing.

That does not mean the fabric is indestructible, however. The test documents its resistance under a defined laboratory load.

Yes. The front fabric has been tested after 7,000 Martindale rotations and achieves a pilling rating of 4/5.

Pilling is the small fibre balls that can form on the surface of textiles through friction.

A rating of 4/5 is a good result and documents high resistance to this type of surface wear.

For you, this means the front fabric is designed to keep a neat, consistent surface appearance through repeated use.

The S3 Long Tights use the original FUSION side pockets, which are developed specifically for sport and movement.

FUSION developed the first tights pockets together with triathlete Aksel Nielsen in 2008. The placement is chosen so that your phone, energy or other small items sit close to the thigh and are easy to reach on the move.

The elastic fabric holds the contents close to the leg, while the construction of the pocket helps keep them in place.

So it is not just an ordinary side pocket. It is a solution refined through many years of practical use.

Yes. The S3 Long Tights have B-Flex reflective details on the lower legs and a reflective logo on the thigh.

The B-Flex reflective material uses glass microspheres that return incoming light back towards the light source.

The material has a documented reflective performance of more than 420 cd/lux·m² and is certified to standards including EN ISO 20471.

It is a well-documented reflective material. For you as a runner, this means the reflective details have a measured ability to return light when they are hit by, for example, car headlights.

The certification applies to the B-Flex material itself and therefore does not mean that the S3 Long Tights as a whole are EN ISO 20471 certified.

The S3 Long Tights are developed for winter training, where the garment is exposed to lots of repeated movement, moisture, weather and washing.

At key stress points, the seams are finished with bar tacks for added durability.

A bar tack is a dense reinforcement of the stitching in places where the construction is exposed to extra strain.

For you, this means exposed areas get extra mechanical reinforcement where the load is typically greatest.

The S3 Long Tights are Made in EU.

The fabrics are produced in Italy, and the tights are sewn in Lithuania.

This gives a European production chain from the specialised technical materials to the finished product, and a close connection between product development and physical production.

The S3 Long Tights are OEKO-TEX® STANDARD 100 certified.

This means that every component of the product has been tested for harmful substances. It therefore covers more than just the fabric itself, including relevant components such as thread, transfers, elastics and labels.

The product is also sewn at an OEKO-TEX® STeP – Sustainable Textile Production certified facility.

Among other things, STeP documents environmental conditions, chemical management, working conditions and safety.

For you, this means documentation covering both the product's components and key aspects of how it is made.

Yes. The Digital Product Passport brings together information on materials, origin, production and the estimated climate footprint, among other things.

The climate footprint is calculated through a Life Cycle Assessment, LCA, in line with ISO 14040 and ISO 14044.

An LCA looks at the product's impact across several stages of its life cycle rather than just one part of production.

For you, this means more transparency and the chance to look beyond the general product claims and see documentation for the specific product.

The S3 Long Tights have a very high overall customer rating.

The recurring argument for the product is its combination of warmth, weather protection and freedom of movement.

That is also the most accurate way to understand the S3 Long Tights: they are developed for the days when cold, wind and rain ask more of your tights than an ordinary run in mild weather.

Because the S3 Long Tights are built as a technical winter product with several specialised materials and documented properties.

The Italian 3-layer front fabric weighs approximately 290 g/m² and is documented across several different areas:

Water pressure: at least 10,000 mm according to EN ISO 20811 – a strong result that documents high resistance to water penetrating the fabric.

Surface water: 100 in the spray test according to UNI EN 24920 – the top score on the scale, and therefore very high resistance to surface wetting.

Wind: a maximum air permeability of 5 mm/s according to EN 9237 – a very low result that documents effective protection against air passing through.

Breathability: Ret ≤18 m² Pa/W according to ISO 11092 – a sensible result for a protective winter fabric, where the balance between weather protection and water vapour transport matters more than maximum ventilation.

Abrasion: at least 20,000 Martindale cycles according to EN ISO 12947-2 – documentation of solid abrasion resistance in laboratory testing.

Pilling: rating 4/5 after 7,000 rotations – a good result for resistance to small fibre balls forming on the surface.

This is combined with a soft, warm inner side, an elastic back, an adjustable waist, the original FUSION side pockets, B-Flex reflective material, bar-tack reinforced seams and European production.

On top of that come OEKO-TEX® STANDARD 100, production at an OEKO-TEX® STeP – Sustainable Textile Production-certified facility, and a Digital Product Passport.

So you are paying for a complete winter solution, where protection, warmth, freedom of movement, storage and documented material data are brought together around running in demanding winter weather.

Because the S3 tackles winter running as a complete system.

Winter tights need to do more than keep you warm. They have to protect against wind and rain, preserve freedom of movement, manage heat while you run and stand up to repeated training through an entire winter season.

That is why the S3 is built with a protective 3-layer fabric on the front of the thighs and knees, where the runner takes the full force of wind and weather, while the back is more elastic and leaves the legs free to work.

What makes the S3 particularly strong is that its properties are backed by concrete test data:

• At least 10,000 mm water column according to EN ISO 20811
• Spray test 100 for resistance to surface water
• Max. 5 mm/s air permeability according to EN 9237
• Ret ≤18 m² Pa/W documenting the fabric's ability to manage water vapour
• At least 20,000 Martindale cycles for abrasion resistance
• 4/5 for pilling after 7,000 rotations
• Certified B-Flex reflective material in relevant areas
• OEKO-TEX® STANDARD 100, meaning every component of the product has been tested for harmful substances. For the runner, this means documented product safety in a close-fitting garment worn directly against the skin under heavy physical strain
• OEKO-TEX® STeP – Sustainable Textile Production at the production site, documenting controlled conditions in areas such as environmental management, chemical handling, working environment and safety

10,000 mm water resistance can also be found in other technical winter tights. What makes the S3 unusual is the combination of documented protection against water and wind, measured breathability, documented durability and a running-specific zoned construction in one and the same product.

On top of that, you get the original FUSION side pockets, bar tack reinforcements, European performance fabrics, full transparency via a Digital Product Passport and production in Lithuania.

That is why we believe the S3 Long Tights are the world's best winter running tights:

Because they combine documented weather protection, freedom of movement, durability and practical running features at a level where very few winter running tights publish an equally comprehensive set of technical data.