This layer fits well over my Icebreaker 260 and a featherweight wool top. With all 3 pieces on it's not constrictive or bulky, everything seems to fit nicely and my movement is not restricted. I can't seem to get over how much this looks like a sweater though, which is a plus since you can wear it in the front country with ease. Another aesthetic point, on the black version there are gray stitches that run the length of the arms and down the torso and across the back. Neither Marmot's site or this one show this so be forewarned, what you see is not what you get. I think it works well as layering piece for colder climbs and hikes, though wearing it without a base layer can be scratchy (either the wool or the cocona stuff, have you ever seen the outside of a coconut?).

THis is listed as WOOL crew but is really less than 30% wool and 70%+ POLYESTER Stick to Patagonia if you want 100% wool Real soft merino wool and leave the polyester for your stiff suits which this one feels like!!!!