Forclaz Trek 100 Down Jacket Review

Overview

The Forclaz Trek 100 is Decathlon’s budget-friendly, packable down jacket aimed squarely at backpackers and travelers who want real 800-fill-power down without paying Arc’teryx prices. Many hikers have discovered it as an alternative to jackets like the Mountain Hardwear Ghost Whisperer 2, which costs more than four times as much. It has since been rebranded as the MT100, but the specs are essentially identical — so if you’re cross-referencing reviews, know that everything written about the MT100 applies here.

Key Specs

Spec	Value
Weight	289 g (10.2 oz, men’s medium)
Temperature Rating	23°F–41°F
Fill Power	800 cuin
Fill Material	90% Grey Duck Down / 10% Grey Duck Feather
Outer Fabric	100% Polyamide (15-denier)
RDS Certified	Yes
Packable	Yes (stuffs into left hand pocket)
Price	~$80–$100
Comparison	See how Trek 100 Down Jacket compares to similar gear

Performance

Warmth

The rated 23°F–41°F range is credible in real-world use — but context matters. When temps dropped into the low 40s in Alaska’s Caines Head State Park, it was all the warmth one tester needed over a base layer. Push below freezing and you’ll need to layer. Below 32°F you’ll want to start layering both under with a base or mid-layer and a shell over the top — one tester wore it as a mid-layer with a base layer and a ski shell in 27°F temperatures and was very comfortable.

The 800 fill power stands out because most higher-end jackets that easily cost 2–3 times as much come with about the same fill power.

Non-hydrophobic 800-fill down performs like down no matter what garment it’s packaged into, and it works just as well as it would in a jacket four times as expensive.

The key word there is non-hydrophobic — more on that under wet weather.

Packability

The Trek 100 scrunches down into its own pocket to the size of a football.

It’s one of the most packable options in its class, rolling down to the size of a Nalgene.

That’s legitimately impressive for an insulated jacket at this weight.

Wet-Weather Performance

This is where you need to manage expectations. The down is not hydrophobic-treated, and while the 15-denier outer carries a DWR finish, the DWR-treated shell does a below-average job against precipitation. In a controlled shower test, the Forclaz soaked through a bit at the top of the zipper, but otherwise stayed dry — no small feat for a jacket that’s merely labeled “weather-resistant.” However, after the test, it soaked through at the seams surrounding both pockets within roughly 20 minutes of drying. Bottom line: trust it for brief light showers, not for sustained rain. Carry a shell.

Breathability & Active Use

During testing, the jacket stayed comfortable during moderate movement in cool conditions, but started to trap heat quickly when the pace picked up or when climbing. There are no features to dump heat — no pit zips, mesh panels, or two-way zipper.

Leaving the hem cinch loose helps a bit with airflow, but once you start sweating, you unzip or shed the puffer entirely.

This is a belay jacket and a camp jacket, not a hiking jacket.

Durability & Zipper

The 15-denier polyamide shell punches above its price point in abrasion resistance. Feathers stayed in and seams stayed tight over a year of use. The weak link is the main zipper. Thanks to a burly face fabric this jacket would have scored higher in durability if it weren’t for a dinky main zipper — testers found it hard to use especially in the cold and prone to separating, though it was fixed easily with a multitool. It’s a known issue and worth flagging: cold, gloved hands will curse it.

Fit & Sizing

Sizing runs consistently small. By all accounts the jacket comes up small — one reviewer who normally wears a large or medium in coats ordered an XL, which was the correct decision. Going with a larger size if in doubt is recommended; if you plan to layer with multiple layers, you may even want to size up two sizes.

The jacket features a slim, athletic fit with a longer hem length and deep, zippered side pockets that remain accessible even when layering.

That longer hem is a genuine win — it won’t ride up under a pack hipbelt the way shorter cuts tend to.

One ergonomic quirk: the neck area goes up high, which sometimes creates rubbing and friction on the lips or chin. The cuffs can also feel a bit too tight, especially if you’re wearing a watch. Neither is a dealbreaker, but worth knowing before you buy.

Pros & Cons

Pros

• 800-fill-power duck down at a price point that routinely undercuts competitors by 3–4x
• RDS-certified fill — ethically sourced and independently verified
• Packs into its own pocket to roughly Nalgene size
• Longer hem stays in place under a pack; doesn’t expose your lower back
• Extended sleeve baffles wrap over the wrist for down coverage even under gloves
• Seams and baffles hold up well over extended use with minimal feather blowout
• 15-denier nylon shell is surprisingly durable for this price

Cons

• Main zipper is stiff, finicky in the cold, and prone to separating
• Down is non-hydrophobic — wet conditions significantly degrade performance
• No ventilation features; overheating while moving is a real concern
• Runs 1–2 sizes small; ordering the right size requires attention
• High collar can chafe chin and lips, especially for taller-necked or bearded wearers
• DWR treatment is only adequate, not reliable in sustained precipitation

Who Should Buy This

The Trek 100 is ideal for weight-conscious backpackers and travelers on a real budget who understand layering. If you’re using it as a mid-layer or a static-camp layer on shoulder-season or three-season trips, it’s hard to argue with the value. It might be the perfect backpacking jacket when layers are essential. When used properly as a layering piece it works well — you won’t be comfortable going out in 20-degree weather with only this jacket, but if you have other layers, it will. Skip it if you hike in consistently wet climates, need a standalone piece in sub-freezing conditions, or plan to move fast and need to vent heat.

Verdict

The Trek 100 delivers a straightforward value proposition: it’s earned a cult following for good reason — a warm, versatile, 800-fill down jacket that delivers incredible performance for the cost. The zipper is a legitimate frustration and the lack of hydrophobic down means you’ll need a shell companion in mixed weather, but neither of those flaws is unusual at this price point. For a budget-conscious backpacker who already owns a rain jacket and understands that this is a layering piece, not an all-weather shell, it’s one of the shrewdest $80–100 you can spend on insulation. I give it a 7.5/10.