What is a membrane and how does it work?
Plain language, no technical fog: how membrane clothing differs from ordinary rainwear, what 10,000 mm and 7,000 g/m² actually mean, and which HARD-TEX® level to pick for what you do.
Short version: a membrane is a layer inside the fabric that keeps water out while letting body moisture escape from the inside. In FINNTRAIL clothing it is called HARD-TEX®, and its strength runs from 10,000 to 25,000 mm. The longer you stay near water and the more pressure there is, the higher the level you need.
What is a membrane?
A membrane is a technical material used in clothing and footwear to make it waterproof, windproof and breathable at the same time. That is why membrane clothing is popular with anglers, ATV riders, hikers and everyone else who spends time outdoors.
Put simply: the rain stays outside, while body moisture and excess heat get out. This is why membrane clothing is usually far more comfortable than an ordinary non-breathable raincoat.
How does a membrane work?
A membrane works as a very thin layer with micropores. These pores are too small for water droplets but large enough for vapour molecules. Water cannot get in, yet sweat vapour can get out.
What is membrane clothing made of?
A membrane is almost never used on its own. It is bonded between other layers so that the fabric is both functional and durable.
| Layer | What it does |
|---|---|
| Outer layer | Protects from mud, water, snow and mechanical wear. |
| Membrane | Stops water droplets but lets body moisture out. |
| Inner layer | Keeps you comfortable and helps moisture move out from the inside. |
How HARD-TEX products differ from each other
The working principle is the same for every membrane. The difference between individual FINNTRAIL products comes down to three things:
- Number of layers. In lighter rainwear the membrane is bonded between fewer layers, while the hardest-working waders use a four and five layer construction. More layers give not only better water protection but also better abrasion resistance.
- Seams. Every membrane FINNTRAIL product has fully taped seams. That matters more than it sounds: a leaking seam lets water through even when the fabric itself does not.
- TEFLON® coating. Some waders (AQUAMASTER, ENDURO, RACHEL, TIMBER BF) add a TEFLON coating on top of the membrane, so water beads off the outer fabric instead of soaking into it.
What does water resistance in mm mean?
The number in millimetres shows how much water pressure the material holds before it starts letting moisture through. The higher the number, the better the protection against long or heavy rain and against pressure.
The general rule that “more mm is better” says nothing in practice. It is more useful to see where one level ends and the next begins. The table below covers the whole range we sell today.
| Water resistance | Breathability | What it is for | Examples from our catalogue |
|---|---|---|---|
| 10,000 mm | 8,000 g/m²/24 h | Rain without standing under it for long, dry snow, city and road conditions. There is almost no pressure on the membrane. | Raincoat DryCoat Graphite 4020 (109 €), Suit RIDER Graphite 3475 (159 €) |
| 12,000 to 15,000 mm | 7,000 to 10,000 g/m²/24 h | Ordinary rain and snowfall, longer time outdoors. The most versatile level for everyday use. | Rain jacket OUTDOOR Graphite 1309 (119 €), Rain jacket APEX Red 4027 (109 €), Suit OUTDOOR SUIT Khaki 3445 (189 €) |
| 17,000 mm | 7,000 to 8,000 g/m²/24 h | Heavy rain, wet snow, and pressure appears: sitting, kneeling, backpack straps. | Waders TIMBER DarkGrey 1538 (159 €), Wading jacket GREENWOOD Grey 4021 (179 €), Suit Thor Graphite 3421 (299 €) |
| 20,000 mm | 7,000 to 10,000 g/m²/24 h | Long spells in water and rain, riding through mud, constant pressure from a seat or from water. | Waders WADEMAN Khaki 1524 (189 €), Waders RACHEL Petrol 1520 (209 €), Rain jacket TOURNAMENT Graphite 4028 (279 €) |
| 25,000 mm | 7,000 g/m²/24 h | The toughest conditions and a full working day in water. This is where the five layer construction is used. | Waders AQUAMASTER Blue 1536 (299 €), Waders ENDURO Graphite 1539 (319 €), Waders SPEEDMASTER 1540 Graphite (349 €) |
Prices and availability checked on 9 September 2026. The exact figures are always shown on the product page.
When 10,000 mm is enough and when it is not
Short answer: 10,000 mm is enough when water only falls on you, and not enough when you press yourself against water.
Standing in the rain there is almost no pressure, so a 10,000 mm jacket holds up perfectly. But pressure appears faster than you would think:
In practice: for a rain jacket 10,000 to 15,000 mm is enough. For a full day outdoors take 17,000 mm or more. For waders look from 20,000 mm, and if you stand in water almost every day, 25,000 mm.
What does breathability in g/m² mean?
Breathability shows how much moisture the fabric moves out from the inside in 24 hours. The higher the number, the more comfortable it is during active movement, when you sweat more.
| Breathability | What it suits |
|---|---|
| up to 5,000 g/m²/24 h | Calmer activity with little movement and less sweating. |
| 7,000 g/m²/24 h | The most common value in our clothing: fishing, wading, riding, a moderate load. |
| 8,000 to 10,000 g/m²/24 h | More movement: walking, working in a boat, a backpack on your shoulders. |
High water resistance with low breathability gives the same result as a non-breathable raincoat: dry on the outside, wet on the inside. That is why both numbers should be read together, not one at a time.
How to quickly understand what you need?
| Situation | What to look for | Where to look |
|---|---|---|
| Rain on the way, calm time outdoors | 10,000 to 15,000 mm | Rain jackets |
| A full day outdoors, hiking, a backpack | 17,000 mm and higher breathability | Rain suits |
| Fishing from a boat, ATV, mud | 17,000 to 20,000 mm | Wading jackets |
| Wading, standing in water | 20,000 to 25,000 mm | Waders |
| Winter, snow machines | 12,000 to 20,000 mm plus insulation | Warm suits |
How to choose the type and size of waders is covered separately in the guide how to choose the best waders.
Membrane clothing vs regular rainwear
Standard rainwear protects against water, but it usually does not breathe. When you move more actively, moisture builds up inside and the result is just as wet, only from the other side.
| Feature | Membrane clothing | Regular rainwear |
|---|---|---|
| Rain protection | Yes | Yes |
| Breathability | Yes | Usually no |
| Comfort during movement | High | Often lower |
| Suitable for active use | Yes | Limited |
Who membrane clothing is not for
A membrane is not the answer to everything, and in a few cases it is simply a bad buy:
- If you are looking for warmth. A membrane stops water and wind, but it does not warm you. Warmth comes from the layers underneath: thermal clothing and insulation.
- If you will only use it occasionally. For a short dash from the car to the door an ordinary raincoat does the same job for less.
- If you do not plan to look after it. Dirt and sweat salts clog the membrane and it stops breathing. It has to be washed with proper care products, not with ordinary detergent, and never with fabric softener.
- If you work near fire or weld. A spark burns through membrane fabric instantly, and the hole cannot be closed again.
- If you expect waterproof to mean forever. The outer coating wears off and has to be renewed with a proofing product. How that is done is written up in the guide how to wash waterproof clothing and waders.
The most common mistakes when choosing
- Looking only at mm ratings and ignoring breathability.
- Assuming “waterproof” automatically means comfort in every situation, when the whole construction matters too.
- Choosing too weak a level for active use or demanding weather.
- Not taking into account that different activities need a different level of breathability.
Frequently asked questions
Will a 10,000 mm jacket soak through in the rain?
No, not if you are simply out in the rain. A jacket like that will hold through a long spell of rain as well. Moisture inside usually does not come through the membrane: it comes from sweat that cannot escape fast enough, or from the fabric being pressed against you somewhere.
What is the difference between 20,000 mm and 25,000 mm waders?
Construction. The 25,000 mm models use a five layer HARD-TEX membrane and often a TEFLON coating, so they take not only higher pressure but heavier use. If you fish a few times a month, 20,000 mm is enough. If you stand in water almost every day, pay for 25,000 mm.
Does a membrane stop working over time?
The membrane itself lasts a long time, but it gets clogged with dirt and the water repellent outer coating wears off. Both are restored by washing with the right detergent and re-proofing. In practice that is one care cycle per season.
What should I choose if breathability matters most?
Look at the 10,000 g/m²/24 h line: you will find it among our rain suits, rain jackets and wading jackets. It is also worth checking on the product page whether the garment has a DWR coating on the surface: when the outer fabric soaks up water, breathability drops even though the membrane itself is working properly.
Can membrane clothing go in the washing machine?
It can and it should, but with a detergent made for membranes, without fabric softener and without bleach. Ordinary detergent leaves additives in the fabric that block the pores, and the garment stops breathing sooner than it would from dirt.
Conclusion and where to start
A membrane is not just another layer of fabric but a technology that keeps water out and lets the body breathe at the same time. Two numbers and one question about yourself decide the choice: mm is water protection, g/m² is breathability, and the level depends on how long and under how much pressure you stay near water.
Where to go next:
- Rain jackets and rain suits: 10,000 to 15,000 mm, for everyday rain protection.
- Wading jackets: 17,000 to 20,000 mm, for a full day in the water and in a boat.
- Waders: 17,000 to 25,000 mm, depending on how often you wade.
- Warm suits: 12,000 to 20,000 mm plus insulation, for winter and snow machines.