The FR-C Pro Lyte Jacket has been the perfect addition to my winter kit arsenal: I love it paired with their ceramic baselayer for temps around the 40s (I tend to run warm). With a thicker baselayer, and on rolling terrain, could do well to colder temps, too. So far, I've worn this down to about 25F with a warmer baselayer doing interval workouts. My favorite part about this jacket is the breathable, jersey-knit, back panel. Most of my rides here in Utah are up a canyon, and back down. Being able to dump heat on the way up keeps me cool and comfortable, wicking sweat so I'm not too cold on the way down. I also love the zip pocket--keeping my wallet (okay, it's a binder clip) close at hand but separate from the pockets I go in and out of during the ride. A small detail that's worth noting: the *real* size zipper pull on the front! So many jackets have these teeny tiny zipper pulls that are near impossible to use with gloves on. Giordana was so intentional with making this a cold weather piece--even with thick gloves, I can easily vent that zipper as needed. The fit is true for Giordana--I went with a large to have room for a long sleeve baselayer. I am 5'6" 145lbs, wear a 28" jean size, and wear a medium bib.