Merino wool anchors the Nova 1/2-Zip Baselayer Top, blended with polyester and elastane for stretch and backed by Responsible Wool Standard certification. The high collar half-zip is what sets this baselayer apart from a standard crew top, adding coverage at the neck and opening in seconds once the pace picks up. What Our Gearhead(R) Experts Are Saying:"I unzipped the collar on the climb and the wool did the rest, pulling heat away without ever feeling clammy. Zipping back up at the top locked that warmth right back in for the descent."