How to Choose Base Layers
REI Co-op Heavyweight Merino Base Layer Bottoms - Men's
$49.83Compared to $99.95* Save 50%
Get ready for adventures in the cold with our warmest merino base layer bottoms yet. Made with 100% merino wool, the men's REI Co-op Heavyweight Merino base layer bottoms are supersoft on the skin.
- Heavyweight 250 g merino wool offers a soft feel without the scratchiness
- Made with 100% merino wool that naturally wicks away sweat, resists odors and dries quickly
- UPF 50+ sun protection
- Soft jacquard waistband is comfortable on the skin—and its low profile allows for easy layering
- Crotch gusset is made for ease of movement
- Functional fly
- Close-to-body fit for optimum performance
- Locker loop makes it easy to hang these to dry or just keep them off the ground
- Inseam length: 29 in.; Tall sizes: 32 in.
- Weight for size M: 8.8 oz. (250 g)
- Machine wash cold, use wool wash product, do not twist or wring, remove promptly; do not bleach; tumble dry low
- 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
Imported.
View all REI Co-op Men's Base Layer Bottoms| Best Use | Multisport |
|---|---|
| Fabric | 100% merino wool |
| Sun-Protective Fabric | Yes |
| UPF Rating | 50+ |
| Moisture Wicking | Yes |
| Quick Drying | Yes |
| Fly Opening | Yes |
| Underwear Weight | Heavyweight |
| Inseam (in.) | 29, 32 inches |
| Gender | Men's |
| Sustainability | Fair Trade Certified™ factory From a Climate Label Certified brand |
REI Co-op Clothing - Men's
| XS | S | M | L | XL | XXL | XXXL | 24 IN Waist | 26 IN Waist | 28 IN Waist | 30 IN Waist | 31 IN Waist | 32 IN Waist | 33 IN Waist | 34 IN Waist | 35 IN Waist | 36 IN Waist | 38 IN Waist | 40 IN Waist | 42 IN Waist | 44 IN Waist | 46 IN Waist | 48 IN Waist | 50 IN Waist | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chest | 35 | 36 - 38 | 39 - 41 | 42 - 45 | 46 - 49 | 50 - 53 | 54 - 57 | |||||||||||||||||
| Sleeve Length | 32 | 32.5 | 33 | 33.5 | 34 | 34.75 | 35.5 | |||||||||||||||||
| Waist | 27.5 | 28 - 30 | 32 - 34 | 36 - 38 | 40 - 42 | 44 - 46 | 48 - 50 | 24 | 26 | 28 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 38 | 40 | 42 | 44 | 46 | 48 | 50 |
| Hip | 33.5 | 34.5 - 36.5 | 37.5 - 39.5 | 41 - 43 | 44 - 46.5 | 47.5 - 50.5 | 51.5 - 54.5 | 32 | 33.5 | 34.5 | 36.5 | 37 | 37.5 | 38.5 | 39.5 | 40.25 | 41 | 43 | 44 | 46.5 | 47.5 | 50.5 | 52.5 | 54.5 |
| Inseam | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 |
Sizing Notes
Measurements are stated in inches unless otherwise indicated. Size chart values represent body measurements, not garment measurements.
SHORT: Some pants are available in short sizes, which generally means an inseam that is 2.5 inches shorter than regular sizes.
TALL: Some pants, shirts, jackets and parkas are available in tall sizes, which generally means an inseam that is 3 inches longer and a rise that is 1 inch longer, a shirt or jacket body that is 2 inches longer, a parka body that is 2.5 inches longer and sleeves that are 2.5 inches longer than regular sizes.
Capri or cropped pants have an intentionally shorter inseam—reference the technical specs instead of this chart.
Inseam is measured to the floor.
Buying Advice
