We learned to appreciate the vest many miles ago. Simple, light, small, easily fits in a pocket, provides just enough protection from the wind, and can be pulled on or taken off easily and quickly when riding. As appealing as the Assos SJ.BlitzFeder Long Sleeve Shell is, we're often inclined to go sleeveless. For this, there's the SV.BlitzFeder Sleeveless Shell.Sleeveless shell. A vest in other words, but Assos is calling it the former to demonstrate how protective it is. Having a windproof barrier between your jersey and the outside gives more protection than a simple vest with a mesh back.At the same time, this sleeveless shell is better at releasing sweat vapor thanks to the new Foil043 fabric. It's feathery light. It's ultra-thin; ball it up and it easily fits in a jersey pocket without sticking out. There's even a stuff sack sewn into the vest. Assos calls the material a 'natural windbreaker,' which is their way of saying that there is no membrane creating the windproof qualities of the material; the structure of the threads and the density of the weave make it so. A treatment is added to give the fabric water repellency. And, as Assos cares about aesthetics, this fabric was engineered not to rustle in the wind. As with all Assos garments, it's designed to fit closely, and it fits best when in the riding position. There is elastic at the shoulders and waist, and it has elastic mesh inserts on the sides of the back and under the arms back to allow some stretch.The Assos SV.BlitzFeder Sleeveless Shell is translucent White. There are reflective tabs on the shoulders and on either side of the waist. Sizes run from X-Small to TIR.