ThruDark Phalanx Fleece review: the fleece I never hike without

This is the fleece I reach for on every hike. It kept me warm through the night on this year's Jurassic Coast ultra, out on an exposed coastal path in wind and driving rain. It was my warm layer up a mountain in the middle of January. And this winter it is the first thing in my case as I head to Northern Finland and minus 25. Putting it on and zipping it up around the neck is instant warmth, and with a wind and rainproof jacket over the top I am set for whatever the weather throws at me; if I start to overheat I just open the outer zip and the fleece still lets the heat escape.

The version you can buy today is the G2, in Polartec Alpha Direct, and that is the fleece this review is about. Mine is the original that ran before it, and I have owned and hiked in it for years, so this is not a first impression: it is why I trust the piece enough to tell you to buy the current one. ThruDark upgraded the outer fabric to Alpha Direct and kept everything I rate about it, and by their own numbers it is just as warm, with better breathability, less weight and more packability.

If you want the full picture on the brand itself, the founders, the fabrics and how the range fits together, that is in the ThruDark brand review. This piece stays on the fleece.

Who the Phalanx is for

ThruDark was founded by two former Special Boat Service operators and runs its operation from Poole, about half an hour from where I hike. The military heritage is real and it shapes the styling: the hook-and-loop insignia patches on the sleeves, the muted colours, the name. None of that changes what the garment is, which is a seriously warm, breathable fleece mid-layer.

It suits you if:

• You want a serious cold-weather mid-layer for hiking, and you layer properly (fleece under a shell, not fleece instead of a shell)
• You feel the cold, moving or stationary. It dumps heat when you are working hard and holds it when you slow down, so it stays usable on the move, not just at rest, which is exactly how I wear mine
• You like the brand and want its best-known piece rather than a lookalike

It does not suit you if:

• You want one jacket that handles wind on its own. ThruDark's own product page rates the Phalanx 2 out of 10 for wind resistance, and they are right to
• You are shopping on price alone. This is a premium piece and it makes no attempt to be anything else

Specs

This is the current G2, the one on sale. Mine is the original that ran before it in Polartec High Loft; the G2 keeps the same warmth and build and upgrades the outer fabric to Polartec Alpha Direct.

Price

£240

Body fabric

Polartec Alpha Direct, 190gsm (54% recycled polyester)

Weight

450g

Zips

2-way YKK reverse coil with zip guard

Pockets

Angled YKK chest and zipped YKK hip pockets, tricot-lined

Seams

Flat-locked

Fit

Regular (ThruDark advise buying your usual size)

Variants

Hooded, in obsidian black or forest green, plus a crew version

Made in

Vietnam

Warranty

5 years, plus lifetime repairs

Brand's own ratings

Thermal 8/10, breathability 8/10, dynamic movement 7/10, wind resistance 2/10, durability 6/10

Rated to

Around -10°C (ThruDark's 'essential' band)

ThruDark publishes these figures on its own product page, including the unflattering ones. A brand rating its best-known product 2 out of 10 for wind and 6 out of 10 for durability is being straight with you, and I come back to the wind number below.

How warm it is

The G2 runs Polartec Alpha Direct, an active-insulation fabric originally developed with US Special Forces for stop-start effort. Instead of a dense, flat pile it uses an open lattice that traps a lot of warm air for very little weight, which is how a 450g fleece ends up feeling this warm. ThruDark rate it 8 out of 10 for thermal performance, the same score as the original I own, and that rating matches what I have felt for years: this is a proper cold-weather mid-layer, not a spring windcheater. Zip it up around the neck and it is instant warmth, and the open structure of the fabric means it keeps breathing while it does it.

Breathability and the layering role

This is where the G2's Alpha Direct really shows. That open-lattice fabric is genuinely breathable, so it dumps heat when you are working hard on a climb and holds it again when you stop, which is exactly what you want from a mid-layer. ThruDark rate breathability 8 out of 10, and the fabric earns it.

That tells you what the Phalanx is: a mid-layer. It sits under a shell on cold days, breathes well enough that you do not soak your baselayer on the climbs, and holds warmth when you stop. Worn that way, with a waterproof over the top when the weather turns, the system just works. On calm, dry, cold days it is a lovely layer on its own too, the frosty still morning, the walk from the car, the campsite evening.

The wind question

One number to be straight about: ThruDark rate the Phalanx 2 out of 10 for wind resistance, on their own product page. A fleece is a warm-air trap with no barrier, so a stiff wind blows through it. That is not a fault, it is what a fleece is. Layer it under a waterproof or windproof shell when the wind gets up, the way any fleece is meant to be worn, and you will not think about it again. Credit to ThruDark for printing the number rather than burying it.

Build quality

The hardware is where the £240 shows up in ways you can point at. The zips are 2-way YKK reverse coil with a zip guard, which is the right answer and not a given at any price. The chest pockets are angled YKK and tricot-lined, the hip pockets zipped and lined too, and the seams are flat-locked so nothing rubs under a pack strap. The binding, hood and cuffs are all cleanly finished.

The insignia patches on the sleeves are hook-and-loop, so you can run the ThruDark patches, swap your own in, or leave the fields blank. It is the most obviously military-derived detail on the fleece and the easiest to ignore if it is not your thing.

It is made in Vietnam and carries a 5-year warranty with lifetime repairs behind it, and that warranty is a real part of the value at this price. ThruDark's own durability rating is 6 out of 10, which is honest: active-insulation fabric is light and breathable by design, so treat the face kindly under heavy pack straps and it will keep going for years, as mine has.

Fit and sizing

ThruDark cut it regular, neither athletic nor baggy, and say to buy your usual size. I did exactly that, took my normal medium, and it is spot on. If you layer a lot, just check your shell has room over the top, because this is a warm fleece and you want it sitting under a jacket without pulling tight across the shoulders.

The £240 question

£240 is a premium price, so here is what it buys. The fabric is Polartec Alpha Direct, an active-insulation textile developed with US Special Forces and one of the best warm-and-breathable fleeces going, in a piece that weighs just 450g and packs down small. The hardware is YKK throughout, the pockets are lined, the seams flat-locked, and up close the build looks like it will still be working in year five. Behind it sits a 5-year warranty and lifetime repairs.

Part of the price is the brand, and I am fine saying that: the ex-Special Boat Service founders, the Poole operation, the fact this is the piece ThruDark is known for. That is how premium kit works, and here the story under the price is real and the garment carrying it is properly made. What you are not paying for, because ThruDark tell you so themselves, is a windproof outer. It is a cold-weather mid-layer, and as one it is excellent.

Pros and what to know

• Polartec Alpha Direct body: seriously warm, genuinely breathable and light at 450g, and it packs down small
• 2-way YKK zips, tricot-lined pockets and flat-locked seams; the build looks the price up close
• 5-year warranty plus lifetime repairs
• ThruDark publishes its own honest ratings, and the fleece matches the billing

• £240 is a premium price: be sure a warm, breathable mid-layer is the job you need filling
• Wind resistance is 2/10 by ThruDark's own rating: layer it under a shell in typical UK hill weather
• The military styling and insignia patches will not be to everyone's taste, even if removable

Which Phalanx to buy

The current line is all G2, in Polartec Alpha Direct. The hooded version comes in obsidian black or forest green, and there is a crew version if you would rather skip the hood. Mine is the original that ran before the G2, I have leaned on it for years, and that is exactly why I trust the upgrade: ThruDark kept the warmth and the build and improved the fabric. They have not let me down yet, and I am quietly tempted by the green.

Verdict

The Phalanx is the mid-layer I actually reach for, season after season, and the one going to Finland this winter. The current G2 does exactly what a great fleece should: serious warmth for the weight, real breathability from the Alpha Direct fabric, quality hardware, and a brand that stands behind it with a 5-year warranty. It is a premium buy, and part of that is the name, but I bought mine knowing exactly that and I have never once regretted it, not on a training walk, a winter dog walk, or halfway through a freezing football match. Layer it under a shell the way it is meant to be worn and it is superb. It is the fleece I never hike without, and the G2 is the one to buy.

Next in this series: the Black Ops Dyneema Jumper review, where I ask whether Dyneema in a cotton sweatshirt means anything. And for the whole picture on the brand, start with the ThruDark brand review.

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