The Castelli Fly Vest boasts all the features that have made Castelli's cycling tops popular, along with exceptional warmth and weatherproofing for its genre that's out of all proportion to its light weight.That's because, while the sides and back are made from stretchy, jersey-weight fabric, the front features Castelli FLY Fabric Technologies (FFT). This means that, just where the elements are most likely to hit you as you ride, you will benefit from the protection of three carefully thought-out layers.First, there's an inner of windproof yet breathable Gore-Tex Infinium™ Windstopper®, then a layer of warmth is added by super light CLIMA SL. Finally, a FLY SL shell sheds water and deflects wind. The latter two layers, additionally, are made from 100% recycled materials, making this vest as eco-friendly as it is efficient.To aid temperature regulation, this vest features a low/no cut collar, which acts to prevent wind from entering at the neck, without offering so much coverage that it might cause you to overheat.It's also practical, featuring as it does some of the essential elements that make Castelli's cycling layers so good. There's ample pocket space, including a zippered valuables compartment, reflectivity and anchorage at the waist, and a top-and-bottom opening zip to aid ventilation.Features:An incredibly light vest offering protection from the elementsCut with a low/no collar for improved temperature regulationWith stretchy, jersey-weight back and sides to ensure a good fit and cut down on weight3-layer Castelli FLY Fabric Technologies (FFT) at the front onlyFeatures windproof, breathable Gore-Tex Infinium™ Windstopper® innerCLIMA SL insulation mid layer is 100% recycled post-consumer and adds warmthWith FLY SL shell, also 100% recycled, for water shedding and wind protectionTop and bottom opening YKK® Vislon® zipperWith 3 good sized back pockets, zippered valuables pocketElastic and silicone waist gripsReflectivity at the hemFor a temperature range of 10-18°CWeighs 99g (M)