While waiting for spring to deliver some better weather falls short of fun, an upside to constantly cool temps here in the Northeast is plenty of opportunity to test gear fit for prolonged seasonal transitions. And since in such weather the mid layer is king, we’ve been on the look out for the best. The most recent to catch our eye is the women’s Quantum Long Sleeve Zip Hood, from renowned merino wool apparel purveyor Icebreaker.

To test the piece we enlisted the help of Alyssa, a friend of The Field and lifelong runner who recently began training for the 2017 New York Marathon. She also works for Maharam, the most important American name in interior textiles design, making her the perfect expert to put the merino mid layer to the test. And because we're style-obsessed New Yorkers after all, we decided to try out both Black and Aura colorways.

At first glance the Quantum appears quite minimal. And it is—you’ll find no unnecessary bells or whistles—but it isn’t too much so. Front zippered pockets flank the sides for warming hands and storing essentials, a drop tail hem extends coverage, and a reflective strip along the front zipper (with a small hit on the rear yolk too) increases visibility in low light conditions. All of which is especially helpful when running daily regardless of weather.

Part of Alyssa's training regiment brings her to Manhattan's West Side Highway running path that parallels the Hudson River and, on mornings when tourist crowds are thin, up and along the historic High Line park path. Rain or shine, the miles have to got to go. Which is why Alyssa was particularly drawn to both the lightweight, single-layer hood—ideal for particularly chilly morning and evening runs—and the small zippered chest pocket with media cord passthrough. “I always get tangled in my headphone cords, so the cord management system is super useful and convenient.”

And since we’re talking about Icebreaker here, material is a major part of the story. The Quantum is made of 98% merino wool with a 2% Lycra addition for just the right amount of stretch. Together the two materials create a high performance fabric with excellent natural benefits, including odor resistance, breathability, and moisture management. The raglan sleeves with mesh underarm help too.

And of course, the Quantum is warm. “The weight to warmth ratio of the merino is impressive. It’s soft, but still does well to keep the wind out,” Alyssa reported, “and has great heat retention too—I don’t feel cold during breaks, waiting at crosswalks, or even on the subway home.”

With just the right amount of performance blended so seamlessly into a classic silhouette, it’s easy to see why the Quantum earned Alyssa’s stamp of approval, and the TF edit team’s too.