Atom Vest M in Habitat from Arc'teryx uses Durable, breathable Fortius Air 20 nylon plain weave, which is lightweight, air-permeable, and made with 42% recycled nylon FC0 DWR (Durable Water Repellent) finish repels moisture and is PFAS-free 40gsm stretch synthetic insulation is breathable, warm, and light, adds freedom of movement, and is made with 85% recycled content Lightweight stretch Octa Fleece side panels provide freedom of movement and enhance breathability Zippered hand pockets secure small essentials Adjustable drawcord at hem seals out drafts Fitted, with ergonomic patterning for mobility, comfort, and easy layering.