Arc'teryx Rho LT Crew vs Smartwool Merino 150 Base Layer Top
Weight and specs compared for 2026 — and which one to choose.
Lightweight Phasic base layer for cool and active conditions.
Lightweight merino wool base layer with excellent moisture management.
Building a pack? Add either one to your HikeLoad list, or drop its weight into the base weight calculator, and see what it does to your total weight.
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Arc'teryx Rho LT Crew vs Smartwool Merino 150 Base Layer Top: which should you buy?
If saving weight is your priority, the Arc'teryx Rho LT Crew wins — at 155 g it is 8 g (5%) lighter than the Smartwool Merino 150 Base Layer Top (163 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.