Warm, not too bulky - Rab Positron Pro Jacket - Women's

My wife runs cold and when the temperatures drop below 20F she will often wear multiple layers under her Rab Electron. This jacket is the perfect solution as it's plenty warm. She is 5' 5" about 130lbs. A small fits well, not too bulky. If you plan on wearing multiple layers under this, I'd suggest sizing up. It does make some minor chaffing noises in the arms when she walks, but that's to be expected from a jacket with this much fill and I don't notice it all of the time. I do wonder why they chose to have the chest pocket accessible from the inside rather than the outside - like the men's, but that's ultimately personal preference.