Arc'teryx Gamma SL Hoody
The Arc'teryx Gamma SL Hoody weighs 8.7 ounces in a women's small and uses Fortius 1.0 double weave fabric (86% nylon, 14% elastane) to create one of the most versatile softshells I've used. The four-way stretch moves with you during scrambles, the DWR coating handles drizzle, and the StormHood adjusts for rain without a helmet. Priced around $225 and now discontinued, though it still shows up on resale sites. The SL stands for Superlight, and at under 9 ounces, you can stuff this into a pack and forget about it until weather changes.
Fortius 1.0 Fabric and DWR Water Resistance
The Fortius 1.0 double weave handles light rain for 20-30 minutes before moisture starts seeping through. That's enough for passing showers and mist, but not for sustained downpours. The DWR coating causes water to bead on the surface. Once it wets out, the fabric dries fast thanks to the thin single-layer construction.
The real strength is wind blocking. The nylon face kills wind without the clammy feel you get from hardshells. I've worn this on ridgelines in 30mph gusts and stayed comfortable. The 14% elastane provides stretch and forgiveness against snags. Rather than tearing on rocks, the fabric flexes.
How Does the Arc'teryx Gamma SL Hoody Fit?
The trim fit sits close without feeling restrictive. It accommodates a thin fleece or baselayer underneath but nothing heavier. Size up if you plan on putting anything substantial beneath it. The torso length drops far enough to prevent drafts at the waist, and the sleeves allow full arm extension without riding up.
The StormHood fits over hats but isn't helmet-compatible. For climbing with a helmet, the Gamma Jacket has a helmet-friendly hood. Two zippered hand pockets with mesh lining double as vents during hard climbs.
Breathability That Keeps Up on Steep Terrain
This is where the Gamma SL separates from windshells and hardshells. The single-layer construction with no backing material maximizes airflow. I've hiked hard uphill in this without developing the swampy interior that GORE-TEX creates during sustained effort. The mesh-lined hand pockets add dump vents when you need them.
The breathability makes it work for trail running in cool weather, ski touring on approaches, and scrambling where intensity varies constantly. The Atom LT provides more warmth but can't match this level of airflow. The Squamish Hoody breathes similarly but offers less weather protection.
Arc'teryx Gamma SL vs. Gamma LT and Outdoor Research Ferrosi
The Gamma LT weighs nearly double at 16 ounces and costs $249. The LT adds helmet compatibility, climbing-friendly pocket placement, and an internal zip pocket. Pick the LT for technical climbing with a harness. Pick the SL for fast-moving activities where packability and weight savings matter.
The Outdoor Research Ferrosi Hoody costs $139 and weighs 13.2 ounces. You give up a few ounces of weight savings but save nearly $90. The Ferrosi has been a crowd favorite for years and handles similar conditions. The Gamma SL's advantages come down to lighter weight, cleaner trim fit, and better stretch.
Worth Hunting on Resale
The Gamma SL is discontinued, but resale prices typically run $100-170 depending on condition and colorway. For the weight savings and breathability, it's worth tracking down if you need a do-everything softshell for three-season mountain use. The durability holds up across multiple seasons of rough use, with reviewers reporting no damage after months of scrambling and bushwhacking.
For current alternatives, Arc'teryx's Gamma Lightweight Hoody fills a similar role in the lineup. The Gamma SL set the template that newer Gamma models follow.