The waffle pattern inside traps in your own body heat, even in windy conditions, but is vented on the back. Comfortably fits under a long sleeve road jersey. Great piece of cold weather layering clothing.
fits well and does the job - material warm and breathable
This is a fantastic winter base layer. Really warm and breathable. With this, another layer and a shell, I was in an assertive group ride and comfortable at 30' this December '22. I'm 6.0, 180lbs ' the medium fits perfect.