Gear Review: I/O Merino Contact Long-Sleeve Crib

A superlight wool base layer that shines 12 months a year

Throughout the fall and winter, our gear editor lived 24/7 in the super versatile I/O Bio Merino Contact Long-Sleeve Crib. This ribbed crew (hence “crib”) wicked sweat so fast, she never had a chance to feel clammy—even on big climbs in the Swiss Alps.

The superfine wool feels lusciously soft and the stretchy fabric conforms like a second skin. “It’s tissue-thin, but it insulates like a synthetic fabric twice as thick. And the ribbing facilitates lightning-quick wicking and drying times by promoting air circulation.” Bonus: The simple styling is good enough for a dinner date, say female testers (the gents preferred on-trail only). $60; 3.6 oz. (w’s M);