REI Co-op Merino 185 Crew Base Layer Top - Men's

This 100% merino wool base layer top from REI Co-op is built for multisport adventure. The ultrafine 185 g/m² wool naturally breathes, wicks sweat, dries quickly, and resists odors and pilling, with a soft feel that won't itch.

Flat seams and merrow stitch construction reduce chafing, while underarm gussets allow a full range of movement. The semifitted cut hugs the body for optimum performance, UPF 30 protection shields from the sun, and a locker loop makes it easy to hang dry.

Key Features

Best Use	Multisport
Shirt Type	T-shirt
Fabric	100% merino wool
Sun-Protective Fabric	Yes
UPF Rating	30
Moisture Wicking	Yes
Quick Drying	Yes
Underwear Weight	Lightweight
Sleeve Length	Short Sleeve
Gender	Men's
Sustainability	Fair Trade Certified™ Factory - From a Climate Label Certified brand

Highlights

• Ultrafine 185 g/m² merino wool offers a soft feel without any itchiness
• Made with 100% merino wool that naturally breathes, wicks sweat, dries quickly, and resists odors and pilling
• UPF 30 sun protection
• Flat seams and merrow stitch construction reduce chafing
• Underarm gussets allow full range of movement
• Semifitted to hug the body for optimum performance
• Locker loop makes it easy to hang this to dry or just keep it off the ground
• Machine wash warm, gentle cycle; use wool wash product; do not twist or wring; remove promptly; do not bleach; tumble dry low; cool iron; dry cleaning not recommended
• Made of wool sourced according to third-party animal welfare standards adopted by REI Co-op brand
• Made in a Fair Trade Certified™ factory
• REI Co-op brand is certified to The Climate Label; we actively fund efforts to reduce carbon emissions across our business and support climate projects around the world

Materials & care

Machine wash warm, gentle cycle; use wool wash product; do not twist or wring; remove promptly; do not bleach; tumble dry low; cool iron; dry cleaning not recommended

Sizing & fit

Fits large based on reviews

How to use

Which material is best?

• Wool: highly moisture-wicking and odor-resistant
• Synthetic: durable and less expensive
• Silk: soft and lightweight for casual activities

Match the temp to the trek

• Lightweight layers: best for moderate to cool temperatures
• Midweight layers: best for cold temperatures
• Heavyweight layers: best for below-freezing temperatures

Find your fit

• Must be close to skin to efficiently wick sweat; should fit comfortably snug
• Base layer is for moisture control; your mid layer is for warmth

From feedback to field testing, all of our gear is dialed-in by REI Co-op members. Their adventures informed every stitch and detail—making for better, longer-lasting gear.

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