Excellent - good from 55-40 degrees
This is my 4th piece in the Xenon line. I also have the bibs, jersey and SO jacket/jersey. Fit it designed for slim bodies. I wear a medium. I'm 5'11, w/ 40" chest. The jacket is comfortable between 45-55 degree range even at base training pace. I've worn a short sleeve jersey or a long sleeve base layer only. I would give it 5 stars except for only having one rear zippered pocket. It is big enough for cell phone and keys but not a lot extra. Sometimes I ride with two pairs of gloves - heavier pair to warm up and then switch to lighter pair. I would not be able to stash the second pair of gloves in the one pocket - it's not a problem if wearing a jersey underneath but there are no pockets on my base layer. This piece is a good bridge for when it is not cold enough for the Xenon SO Jacket but a little more is needed than just a vest.