The Bormio Vest is a great addition to your chilly rides. It does a great job of blocking the wind, and completely unzips when the temperature rises. And when it gets really hot, stows nicely in the back pocket. The armpits lack a significant amount of elastic, but the bottom hugs the waist securely. I'm 5'5", 142, 37.5" chest, 29" waist...and purchased a medium. A small would have been a great fit by itself, but would not have allowed for much layering. Best clothing addition of the year, for me.