This is a great lightweight pullover. Warm and easily layerable, either below or on top. I will say, if you are between sizes, get the smaller size. I usually wear XL or L (5'10", 46in chest, 33in sleeves, 36" waist). I wear an XL in all of Arc'teryx's softshells, can wear a L Theta or Alpha hardshell, but I am definitely a Large in this top. Ordered the XL and it is extremely long (longer than the bottom of my Large Theta AR (which runs low), and the waist was big enough for 40"+ waist. I returned the XLs and order Large. Very comfortable (soft), nice taper fit, but not tight. A steal on SAC!