evo.com | Arc'teryx Long Underwear Tops > Dawn patrol in single digits calls for more than a basic base layer. The Arc'teryx Rho SV Zip Neck Top pairs heavyweight Polartec(R) Power Stretch(R) Pro fleece with a tall collar and a deep front zip that dumps heat fast on the climb. A smooth nylon face layers cleanly under your shell, and a zippered sleeve pocket stashes small essentials. Polartec(R) Power Stretch(R) Pro 53% Polyester / 38% Nylon / 9% Elastane Rho Thermally efficient base layer with excellent moisture management properties. Has stretch comfort. Deep Front Zipper for Easy On and Off and Rapid Ventilation Fitted Arc'teryx's trimmer fit is patterned to stay close to the body through the chest, waist, hip, and thigh. Its low profile eliminates bulk, moves with the body, and fits comfortably under outer layers. Sleeve Pocket with Zip | Women's Arc'teryx Rho SV Zip Neck Top 2026 - Small Purple | Nylon/Elastane/Polyester