Materials

Marmot partnered with 3M Thinsulate to populate a line of jackets with their Featherless synthetic insulation. The material nicely emulates 700-fill power down in softness and compressibility, but isn’t nearly as light as the real thing, especially when sewn behind Marmot’s polyester MemBrain weatherproof shell; however, it is warm, and when combined with tough shell exterior, is not subject to suffering under wet conditions.

Chest and arm pockets have waterproof YKK zippers, a smart choice considering they will most often hold a smartphone or snacks. The main zipper, pit-zips, and hand-warmer pockets are also by YKK, but lack the water-resistant construction of the chest pockets. There’s a broad swath of brushed tricot, a polyester fleece, inside the collar and against the face, and the internal lining is also a soft polyester.

Weatherproofness

The Marmot Corkscrew Featherless handled all conditions admirably, brushing off cold rain and wet snow without wetting out. Cold and dry powder wasn’t an issue either, and it fights off wind like a hard shell. The Featherless insulation is no-doubt a top-of-the-line hydrophobic synthetic in terms of warmth, but it’s held in place by two layers of fabric, adding weight.

It proved to be too much jacket for a 30-degree mid-winter warm spell, but ideal for colder times. Outside of extreme temps, this jacket will require little more than a light mid-layer to keep its wearer dry and comfortable.

Temperature Control

The coat had a hard time maintaining temperature control consistency, as the “core vents” are somewhat small at 7.5 inches long. While Marmot’s MemBrain is physically tough against hard edges, general thrashing, and wetness, it didn’t breathe as intended, perhaps a byproduct of being two layers, used in conjunction with the Featherless insulation and polyester lining. One wearer felt sweat forming after two resort laps, and unzipped it completely after the fourth.

Fit/Comfort

Designed for active winter pursuits, the Corkscrew Featherless is roomy enough for significant base- and mid-layers, but adults won’t feel like a juvenile park patron swimming in a cloak of baggy material. It moves well, is generally comfortable to wear as an everyday piece (in cold climes, of course) and strikes a nice length to fully cover the waistline, even when active.

The abundance of pockets (7) means users will feel obligated to fill them. Doing so will result in a very heavy jacket and the urge to dump everything after a few minutes.

The removable hood is large enough to be an annoyance, hanging over the eyes when a helmet isn’t present, suggesting the hood is meant only to work in unison with head protection. The primary tester was 5’9’’, 170 pounds, testing a medium.

Features

The Marmot Corkscrew Featherless can be stripped down by removing the hood and powder skirt, making it a nice option for moderate adventures or in-town use. There are too many pockets, but the wrist/forearm pocket is a nice touch because whatever is in it becomes unnoticeable. The core vents are short, given the warmth this coat can retain. Each hem-tensioning pull has an ergonomic rubber tab that could be found easily with gloves, and the adjustable hood, while large on its own, fit snugly over helmets and bulky beanies. Zipper garages and Velcro straps to tighten the cuff round-out the array of features on this snow-oriented insulated jacket.