REI Co-op Merino Wool Base Layer Crew vs Smartwool Merino 150 Base Layer Short Sleeve

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

Smartwool Merino 150 Base Layer Short Sleeve is the lighter option — 57 g lighter than the REI Co-op Merino Wool Base Layer Crew (30% less weight). If grams matter to you, that is the one to beat.

Spec	REI Co-op Merino Wool Base Layer Crew	Smartwool Merino 150 Base Layer Short Sleeve
Weight	190 g · 0.190 kg · 0.42 lb	133 g · 0.133 kg · 0.29 lb
Brand	REI Co-op	Smartwool
Category	Clothing - Base Layer	Clothing - Base Layer

REI Co-op Merino Wool Base Layer Crew

190 g

Budget-friendly merino wool base layer for backpacking.

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Smartwool Merino 150 Base Layer Short Sleeve

133 g

Lightweight 150g/m² merino wool short-sleeve base layer with natural odor resistance, ideal for warm-weather hiking and backpacking.

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REI Co-op Merino Wool Base Layer Crew vs Smartwool Merino 150 Base Layer Short Sleeve: which should you buy?

If saving weight is your priority, the Smartwool Merino 150 Base Layer Short Sleeve wins — at 133 g it is 57 g (30%) 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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