Extreme Cold Safety Boot Satellite S3S — CXS
Protection Extreme Cold
Insulation 3M Thinsulate 200 g
Weight 746 g in size 43
Thermal protection −25 °C / −13 °F*
3M Thinsulate 200 g Deep-winter warmth at the weight of a walking shoe
Thinsulate 200 g under a single-piece upper, at 746 grams
The Satellite S3S brings together two things that rarely go together: full winter insulation and the weight of a walking shoe. Its 3M Thinsulate 200 g lining fills the whole boot, and its PU-PU outsole carries the CI marking, insulation against cold. The upper is water-repellent split nubuck, 1.6 to 1.8 mm thick, cut from a single piece: there is no side seam where water usually gets in. It is backed by a breathable, abrasion-resistant mesh lining and protected by a PU overcap across the front of the foot. On the safety side, a plastic toe cap and a Dyna-Flex® penetration-resistant midsole, with no metal parts at all. The outsole is antistatic, oil resistant and slip resistant. Reflective details, reinforced heel. Sizes 36 to 49.
Grand-Froid expert's view
This is the lightest insulated winter boot we stock, and the only one you forget you are wearing after an hour on your feet. A single-piece upper also means a boot you clean with one sweep of the brush.
What is it designed for?
This boot is made for jobs with a lot of walking in the cold, and for those where metal is a problem.
- Heavy walking in the cold: patrols, surveys, rounds, sprawling sites
- Airport and port areas: aprons, quays, repeated passes through security screening
- Muddy or snow-covered ground: the single-piece upper brushes clean and dries without holding soil
- Construction and structural work: the PU overcap takes the knocks and the rub of rubble
- Winter days and outdoor jobs: its weight and flex make it wearable for a whole day
Thermal protection
3M Thinsulate is a web of microfibres far finer than a conventional insulating fibre: for the same thickness, they hold more still air, and it is that air that insulates. The 200 g weight is the heaviest of the three commonly used in work footwear. It is also what explains the weight of the boot: here, insulation is not paid for in thickness or in grams.
Underfoot, the PU-PU outsole carries the CI marking. That is not a marketing claim but a test: the whole boot spends thirty minutes at −17 °C / 1 °F, and the temperature measured inside must not drop by more than 10 °C.
That leaves moisture, which ruins an insulation as soon as it reaches the fibres. This is where the single-piece upper counts: a conventional boot is assembled from several panels of leather, and every side seam is a possible way in. Remove those seams and you remove that many entry points. The water-repellent nubuck does the rest on the outside, the breathable mesh lining moves vapour out on the inside.
Specifications & Composition
- Insulation: 3M Thinsulate lining, 200 g weight
- Standard: EN ISO 20345:2022, class S3S FO SR CI
- CI — outsole insulation against cold
- FO — oil-resistant outsole · SR — slip-resistance test on ceramic tile with glycerine
- Upper: water-repellent split nubuck, 1.6 to 1.8 mm, cut from a single piece
- Lining: breathable, abrasion-resistant mesh
- Plastic toe cap and Dyna-Flex® penetration-resistant midsole, with no metal parts
- PU overcap across the front of the foot and reinforced heel
- PU-PU outsole, antistatic and slip resistant
- Reflective details
- Weight: 746 g per half pair in size 43
- Certified by CTC Lyon, notified body no. 0075
Size guide
European sizes, from 36 to 49. Take your usual size: the Thinsulate insulation is thin and does not eat into the space inside. The table gives the insole length — measure your foot flat on a sheet of paper, from heel to longest toe, and take the size whose length exceeds yours by about a centimetre.
Rule number one: keep the foot dry. It is moisture, far more than the outside temperature, that cools a foot as the day goes on. Wear a mid-weight wool sock, which absorbs perspiration and moves it away from the skin. If your feet sweat a lot, take half a size up to leave room for it, and carry a second pair of socks to change at midday: that is the one habit that changes everything.
| Size (EU) |
36 |
37 |
38 |
39 |
40 |
41 |
42 |
43 |
44 |
45 |
46 |
47 |
48 |
49 |
| Insole length (cm) |
23.4 |
24.1 |
24.7 |
25.4 |
26.1 |
26.7 |
27.4 |
28.1 |
28.7 |
29.4 |
30.1 |
30.7 |
31.4 |
32.1 |
Actual dimensions may vary by 0.5 to 1 cm depending on production.
Care & Durability
- Brush the nubuck dry after use, with a soft-bristled brush. The single-piece upper has no seam where mud settles, so one pass is enough
- Bring the nap back with a nubuck eraser on the areas rubbed shiny
- Apply a nubuck waterproofing spray about once a month in daily use, and after every deep clean, to keep the upper water repellent
- Dry at room temperature in an airy room, away from a radiator or a stove — direct heat stiffens the leather and weakens the bonding
- Take the sockliner out in the evening and leave the boot open, so the insulation dries between two days
- Keep away from rich creams and greases, which clog the nap and turn nubuck into smooth leather
Return or exchange — 30 days
You have 30 days after receipt to request a return or exchange for this item.
Why choose the Satellite S3S boot?
Because it does not ask you to choose between warmth and weight. The Thinsulate 200 g fills the whole boot, the outsole has passed the test for insulation against cold, and the boot still comes in at 746 grams.
The single-piece upper is the other reason. On an assembled boot, it is the seams that go first and let the water in. Here there are none on the sides: fewer weak points, less upkeep, and a leather you brush clean in one go.
* Indicative temperature. Perceived warmth varies with activity, body type, humidity, the ground and the socks worn.
