ELIZABETH B I own this exact jacket in a size small, and the fit is awesome. I'm actually on my third one. I wouldn't necessarily call it a slim fit, but it definitely isn't baggy. For me, I have room to wear at least one long sleeve layer underneath, and I think I've probably done 2. I normally wear a small in most everything, so the sizing is pretty standard.

NANCY W The R1 Full-Zip Jacket for Women is not at all bulky, but I wouldn't call it a slim fit either. I can easily wear a T-shirt or long underwear underneath this jacket.

NANCY B The R1 full-zip jacket for women is a straight, slim fit. It works extremely well under a wind shell for cool to cold weather aerobic activities like biking, hiking and xc skiing.