This is a great lightweight baselayer for active pursuits. This with only a tshirt underneath kept me warm while hiking in 40 degree weather. Great athletic fit with nice thumb holes and chest pocket. Is slim enough for easy layering with a vest or shell
Planned to wear this baselayer for winter golf under a down shirt and a Primaloft jacket. But it was so toasty that I took off the jacket within 15 minutes. When the temperature rose to 45º I took off the down shirt too, and just wore this baselayer. Not only was it warm enough to wear alone, it looked good too.