Skiers and climbers who run cold will appreciate the Arc'teryx Rho SV Men's Zip Neck, the warmest base layer top Arc'teryx builds in this line. A heavyweight hollow-core fleece delivers serious warmth for its weight, breathes on the move, and resists shedding for long-term durability. It is the deep-winter foundation layer for activities in severe cold.

Why we like it:

The standout is just how much warmth it offers for the weight, thanks to the hollow-core fleece. Add a tall collar and a phone-sized chest pocket and it is a base layer built with real days in mind.

Features and Functions:

The men's Rho SV uses 210 gram hollow-core fleece with a standout warmth-to-weight ratio, engineered to minimize shedding and made with recycled content. A deep front zipper vents heat and eases layering, a tall collar adds coverage, and a low-profile laminated chest pocket holds small essentials and most phones, while articulated patterning and stretch keep it mobile.

Fit and Sizing:

A fitted cut with articulated patterning and stretch layers easily and moves with you. True to size, with a snug performance cut.

Bottom Line:

For severe cold and active winter pursuits, the Rho SV Zip Neck is best at top-end base-layer warmth without dead weight. The warmest base layer to anchor a deep-winter kit.