Two waterproof/breathable fabrics paired with a stowable hood for durability and solid performance in a lightweight, compressible package.
When a soggy morning turned into a damp but warm afternoon, the Arc'teryx Theta SL kept me dry and comfortable, even in the humid Virginia air thanks to its well thought out features.
By combining Gore-Tex Paclite fabric (Gore's thinnest, lightest fabric) in the main body with more durable Pro Shell in the shoulders, arms, and hood to resist pack wear and branch snags, the Theta SL is light without sacrificing toughness.
The hood is easily stowable in the collar for a less obtrusive fit, particularly when wearing a pack. Twin zippers make deploying the helmet-compatible hood easy to do without taking the jacket off.
The pitzips are short, about 10 inches, to cut down on bulk and weight. They still provided adequate ventilation for fast hiking in 60 degree weather, and use watertight zippers to keep out any water or wind gusts when shut.
Arc'teryx is known for impeccable details, like small seam allowances of only 1.3 mm that let the seams be sealed using thinner and lighter tape, and smart details like zipper garages.
The jacket squeezes down to a circle about 7 inches across and 2 inches thick, so it doesn't take up much pack space when not needed.
The hem rides well below the waist, almost covering my entire seat. The drawstring at the bottom can be cinched tight for protection against wind, or kept loose for better ventilation and a "tent" effect to help shield your legs.