Heading out to play hard? The REI Co-op lightweight base layer crew top keeps you warm until you warm up, then wicks sweat to maintain your cool when you're charging.

Underwear TopsBase Layer Tops

First half-mile cold; next 3 miles sweaty; lunch break cold. Don't stress—the REI Co-op lightweight half-zip long-sleeve base layer wicks and breathes to keep you comfortable all day.

Underwear TopsBase Layer Tops

The men's REI Co-op lightweight long-sleeve base layer crew keeps you warm until you warm up, then wicks sweat to keep you comfortable when you're going hard.

Underwear TopsBase Layer Tops

What could possibly keep you warm until you warm up, then keep you comfortable when you start sweating on the trail? The men's tall REI Co-op lightweight long-sleeve base layer crew is what.

Underwear TopsBase Layer Tops

The REI Co-op lightweight base layer zip-neck top in men's tall sizes knows how to keep you comfortable through a whole day of changes from cold to warm to sweaty and back to cold again.

Underwear TopsBase Layer Tops

No matter what weather you're running in, the On Lightweight cap is here for it with the protection, ventilation and fast-dry performance you need to show up at your best.

HeadwearHats

When you need to scroll and tap a screen out in the cold, the Black Diamond Lightweight Screentap gloves provide lightweight stretch and warmth with full-finger and palm touch-screen compatibility.

Fleece Gloves and MittensFleece Gloves - DEPRECATED

Make life easier with these men's On Lightweight shorts—stretchy running shorts that are easy to wear, easy to perform in and easy to choose as your go-to for run after run.

ShortsRunning Shorts

A lightweight version of the Patagonia classic, the men's Patagonia Lightweight Synchilla Snap-T pullover is made with soft, durable, midweight Synchilla® fleece for cozy warmth on chilly days.

ClothingSweaters and Sweatshirts

A Patagonia classic in a warm, double-faced fleece, this Patagonia Lightweight Synchilla Snap-T fleece pullover is soft and lightweight yet warm, and crafted in durable 100% recycled polyester.

ClothingSweaters and Sweatshirts

Including a lightweight Ubertube and 3 disposable mask filters, the Outdoor Research Essential Lightweight Ubertube Kit offers protection from the elements and filters the air you breathe.

HeadwearBuffs

Whether trekking or training, the Black Diamond Lightwire Tech long-sleeve T-shirt is built to handle it all. Its quick-dry, moisture-wicking performance fabric will keep you moving in cool comfort.

Shirts ParentShirts

Whether trekking or training, the Black Diamond Lightwire Tech T-shirt is built to handle it all. Its breathable, quick-dry performance fabric with 4-way stretch will keep you moving in cool comfort.

Shirts ParentShirts

A classic cross-country style, the AUCLAIR Lillehammer men's gloves pack insulated warmth inside a durable exterior pairing stretchy, breathable backs with supple leather palms.

Gloves and MittensWarm Gloves and Mittens