How to Choose Base Layers

This product is not available.
The REI Lightweight long underwear bottoms are an excellent performance insulation layer.
Shop similar productsImported.
View all REI Co-op Men's Base Layer Bottoms| Best Use | Multisport |
|---|---|
| Fabric | Polyester |
| Sun-Protective Fabric | Yes |
| Gender | Men's |
| Sustainability | From a Climate Label Certified brand |
Adding a review will require a valid email for verification
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.

