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Arc'teryx Rho LT Crew vs REI Co-op Merino Wool Base Layer Crew

Weight and specs compared for 2026 — and which one to choose.

Arc'teryx Rho LT Crew is the lighter option — 35 g lighter than the REI Co-op Merino Wool Base Layer Crew (18% less weight). If grams matter to you, that is the one to beat.
Spec Arc'teryx Rho LT Crew REI Co-op Merino Wool Base Layer Crew
Weight 155 g · 0.155 kg · 0.34 lb 190 g · 0.190 kg · 0.42 lb
Brand Arc'teryx REI Co-op
Category Clothing - Base Layer Clothing - Base Layer
Arc'teryx Rho LT Crew
155 g

Lightweight Phasic base layer for cool and active conditions.

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REI Co-op Merino Wool Base Layer Crew
190 g

Budget-friendly merino wool base layer for backpacking.

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Arc'teryx Rho LT Crew vs REI Co-op Merino Wool Base Layer Crew: which should you buy?

If saving weight is your priority, the Arc'teryx Rho LT Crew wins — at 155 g it is 35 g (18%) lighter than the REI Co-op Merino Wool Base Layer Crew (190 g). That said, the heavier option may justify the extra grams with more capacity, durability or comfort, so weigh the trade-off against how you'll use it.

See where both rank against everything else in this category on the lightest clothing - base layer page, or browse the full gear weight database.

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