Thermal sweater Finntrail POLAR JACKET Black 1391
Code: 1391Black-XS-
Finntrail · Mid layer
Finntrail POLAR JACKET Black 1391 Fleece
A warm Polartec® fleece jacket with a high collar and plenty of pockets, made to wear on its own or as a mid layer under an outer jacket. The Polartec® fleece breathes and wicks sweat, so you stay warm and dry, while the high stand-up collar shields your neck from cold wind. A central SBS zip plus side, chest and sleeve pockets make it handy every day.
Who it is for
Made for warmth and convenience, when you want a fleece layer with plenty of room for small items, good both on its own and under a jacket.
- •For fishing, off-road and hiking as a mid layer under a jacket.
- •For cool days in town and outdoors as a standalone warm fleece.
- •For outdoor work and leisure, when you need many pockets for small items.
When it shines
Best from cool autumn into winter cold: as a mid layer under a jacket on a cold day, or as a standalone fleece in cool weather. Useful from −25 to +10 °C, depending on activity and outer layer.
Technical specs
Materials & technology
Polartec® fleece
A light, hypoallergenic fleece breathes and wicks sweat away from the skin, holds heat both moving and standing still, and for its weight is about a third warmer than wool.
High collar and central zip
The high stand-up collar shields your neck from cold wind, and the central SBS zip lets you adjust warmth and ventilation quickly.
Plenty of pockets
Two zipped side pockets, a chest pocket and a sleeve pocket keep small items safely to hand, even when worn under a jacket.
Reinforced shoulders and anatomical cut
Reinforced shoulders resist abrasion under a jacket or backpack, while the anatomical cut and stretchy fleece let you move freely.
How it differs from an ordinary fleece sweater
Care
Wash up to 30 °C with a detergent made for fleece (Mountval Polar Wash), without softener: it coats the fibre and the fleece stops breathing. Odour is handled by a rinse-cycle freshener (Mountval Silver Freshness). Dry on low heat, not near a radiator or an open fire. Store dry, in a ventilated place.
Frequently asked questions
What is this jacket for?
It is a men's fleece jacket you can wear as a standalone warm layer in cool weather or as a second (mid) layer under an outer jacket. The high collar and plenty of pockets make it versatile.
What is it made of?
From Polartec® fleece. It is a light, hypoallergenic material that breathes, wicks sweat away from the skin and is about a third warmer than wool, while the shoulders are additionally reinforced.
Can it be worn under a jacket and on its own?
Yes. It is thin enough to sit well as a mid layer under a jacket, and warm and tidy enough to wear on its own, even for everyday use.
What season is it for?
Useful from −25 to +10 °C, so it suits cool autumn through winter into spring. Warmth also depends on the outer layer and on movement.
How do I wash it?
Wash up to 30 °C with a fleece detergent (Mountval Polar Wash), without softener. Odour is handled by a rinse-cycle freshener (Mountval Silver Freshness); dry on low heat, not near a radiator.
What about warranty and returns?
We offer a 2-year warranty, you can return within 30 days, and delivery from our Vilnius warehouse is free with a tracking number.
Peace of mind
Warranty
2-year warranty. We resolve manufacturing defects quickly, without bureaucracy.
Returns
Not right? Return within 30 days. We’ll help you pick another size.
Delivery
Free delivery from our Vilnius warehouse with a tracking number.
Not sure about the size or whether it suits your activity? Message us, we’ll reply quickly and honestly.
And if you want an answer even faster, ask the Finntrail AI assistant (the ASK button on the page), you’ll usually get a reply right away.
How to Choose the Correct FINNTRAIL Men’s Thermals Size
Choosing the correct FINNTRAIL thermal clothing size ensures comfort, freedom of movement, effective layering and proper protection from weather conditions. A size that is too small may restrict movement and feel tight around the chest or shoulders, while a size that is too large may reduce heat retention and overall fit.
The size chart shows body measurements, not garment measurements. FINNTRAIL gear is designed with extra room for comfort and movement, so sizing should be selected according to your body measurements.
Measure Your Chest Girth
Measure around the fullest part of your chest, keeping the measuring tape horizontal. Stand straight and keep the tape close to the body, but not tight.
How to measure: measure around the widest part of your chest while breathing naturally and keeping your body relaxed.This measurement is especially important when choosing jackets and the upper part of a suit.
Measure Your Waist and Hips
Measure your waist at the narrowest part or where you usually wear your pants. Measure your hips around the widest part.
Important: do not pull in your stomach and do not tighten the measuring tape too much. The gear should leave enough room for movement, base layers and comfortable sitting.If you are choosing a suit or pants, hip and waist measurements are just as important as height.
Measure Inseam and Sleeve Length
Inseam is measured from the crotch to the inside of the ankle. Sleeve length helps determine whether the jacket sleeves will properly cover your arms during active movement.
Recommendation: check these measurements if you are taller, have longer arms or legs, or are choosing between a standard and a longer size.How to Use the Size Chart
Measurement Description Height Body height in centimeters. Chest girth Chest circumference measured around the fullest part of the chest. Waist girth Waist circumference. Hips Hip circumference measured around the widest part of the hips. Inseam Inside leg length from crotch to ankle. Sleeve Sleeve length. First, choose the size according to the main girth measurements — chest, waist and hips. Then check whether the selected size matches your height, inseam and sleeve length.
Reference Size Chart
Size Height Chest Waist Hips Inseam Sleeve XXS 158–162 80–86 70–76 82–88 53–57 53–57 XS 163–167 84–90 74–80 86–92 53–57 55–59 S 168–172 88–98 78–88 90–100 57–61 57–61 SK 168–172 100–110 90–100 102–112 57–61 57–61 M 173–177 96–102 86–92 98–104 57–61 59–63 MK 173–177 108–117 98–106 110–118 59–63 59–63 ML 180–190 96–102 86–92 98–104 63–65 63–65 L 178–182 100–110 90–100 102–112 61–64 61–64 LK 178–182 119–125 106–114 118–128 61–64 61–64 XL 183–187 108–117 98–106 110–118 61–64 63–65 XLK 185–190 124–133 114–122 126–134 63–65 63–65 XXL 185–195 116–125 106–114 118–127 63–65 64–67 XXXL 190–200 124–133 114–122 126–134 65–69 65–69 What Do K and L Size Markings Mean?
S M L XLStandard sizes for men with average body proportions.
MLLonger size for taller users whose girths match size M but who need extra length.
SK MK LK XLKWider sizes for larger chest, waist or hip measurements.
XXL XXXLLarger sizes for taller users or broader body types.
If You Are Between Two Sizes
If your measurements fall between two sizes, choose according to how the gear will be used. Jackets and suits should leave enough room for base layers, while thermals should fit closer to the body without restricting movement.
- If you are choosing a jacket or suit, the larger size is usually the safer choice.
- If you are choosing thermal clothing, the fit should be close but not tight.
- If height matches one size but girths match another, prioritize girth measurements.
- If you will wear additional layers, leave more room.
Important: technical gear should not be too tight. Fabric under tension wears faster and may restrict membrane performance and freedom of movement.Recommendation Before Ordering
Before ordering a FINNTRAIL jacket, suit or thermal clothing, accurately measure your main body parameters. Take measurements while wearing a thin base layer or clothing similar to what you plan to wear under the gear.
Best result: provide your height, chest, waist and hip measurements. If possible, also include inseam and sleeve length.Summary
To choose the correct FINNTRAIL men’s jackets, suits or thermals size, the most important measurements are height, chest girth, waist girth, hips, inseam and sleeve length. A correctly selected size ensures comfort, layering ability, freedom of movement and effective protection for active use.
Product Care Instructions
- Wash membrane clothing only with special detergents, such as Mountval Wash & Care, at a temperature no higher than 30 °C, without fabric softeners or bleach.
- After washing, restore water repellency using Mountval Waterproofing Refresher (wash-in) or a spray-on impregnation, following the product instructions.
- After impregnation, allow the product to dry naturally.
- Repair minor membrane damages with special glue, such as Aquaseal / Aquasure, only on clean and dry surfaces.
- Clean boots by hand, do not use a washing machine; if needed, use impregnation products designed for technical footwear.
Regular care helps maintain water repellency, breathability, and prolongs the product's lifespan.
For more information on how to clean Finntrail clothing and boots after use, see here.
Product delivery
We receive goods at our central warehouse twice per week: on Tuesdays and Fridays.
Depending on the order submission time, goods are included in the corresponding delivery cycle:
Order submission time Goods received Notes Until Tuesday 09:00 Friday Standard schedule. Until Friday 09:00 Next Tuesday Orders placed after 09:00 are moved to the next cycle. Important Due to holidays, inventory checks or other circumstances, delivery may be delayed by 1–3 days.
- Orders are shipped the same day they arrive at the central warehouse.
- Delivery is available to all parcel lockers in Lithuania or by courier to your home.
- Delivery is free of charge.
Returns
Please inform us about a planned return by email at pagalba@finntrail.lt or by phone +370 614 98366.
- Products can be returned within 30 days from the date of receipt.
- The returned item must be unused, with all tags attached and in the original packaging.
- Returns are completely free.
- Together with the notification about the delivered parcel you will receive a return code allowing you to return the item via any parcel locker.
Available solutions after returning the product:- We will replace it with another size.
- We will suggest the most suitable alternative.
- The refund is issued within 1–2 business days after receiving the returned item.
Membrane waterproofing and breathability
Membrane fabric is usually described using two numbers, often separated by a slash: waterproofness and breathability. The first number indicates waterproofness, the second indicates breathability.
?Waterproofing
This is a sliding scale measured in mm that shows how high a column of water you can suspend over the membrane before it starts to let moisture through.
Waterproof Rating Conditions 0–10,000 mm Light rain, dry snow, light pressure. 11,000–15,000 mm Moderate rain, average snow, light pressure. 16,000–20,000 mm Heavy rain, wet snow, some pressure. 20,000 mm+ Heavy rain, wet snow, high pressure. ?Breathability
This is the amount of moisture by weight that can pass through one square metre of fabric over a period of 24 hours. It is commonly measured in g/m²/24 hrs.
Breathability Rating Level of Breathability 0–5,000 g/m²/24 hrs Low – light exercise. 5,000–15,000 g/m²/24 hrs Medium – medium to high energy activity. 15,000 g/m²/24 hrs+ High – vigorous sustained activity.
