93% Merino wool, 7% spandex
Here's what other sites are saying:
If you're in need of a lightweight baselayer, but don't want coverage down to your ankle, the Stoic Men's Merino 200 3/4-Length Bottom is the one. When the temps start to rise from winter lows, enlist the power of merino wool to keep your muscles warm without overheating. Highly breathable and ultra-soft, this natural fiber also does a tremendous job with moisture- and odor-management. The Y-Elastic waist band and flatlock seams are designed to limit rubbing and keep your mind on your tricky route when you're on the move.
- Backcountry.com refers to the men's version