Vests may seem like a simple item, but they've been essential items for serious cyclists for generations for good reason. They protect the core, allow great ventilation when necessary, can be combined with arm warmers when more insulation is in order, and they're both lighter and more easily packed away than their jacket counterparts. And the Castelli Velo Vest is among the top offerings out there, with great wind protection and good breathability in an extraordinarily lightweight and small package. The Castelli Velo Vest weighs just 69 grams, and the mesh collar both provides extra comfort and acts as a stuff sack for compressing the vest down to next to nothing. The Velo Vest's ForceField ripstop fabric offers total wind protection, and the DWR treatment keeps water at bay, too. The mesh side panels provide extra ventilation, but are also vulnerable to heavy rains the Velo Vest will take the edge off of a wet ride, but this isn't your go-to setup on its own on heavy downpour days. The Velo Vest's long tail keeps the back covered and protected, even when you're in the drops, hammering away. And reflective tabs in the back enhance rider visibility and safety in low-light conditions. They come in a plethora of colors, too, from traditional to bright for extra visibility on the road. Throw a Velo Vest in your pocket on moderate to mild weather days as insurance there's no weight penalty, and it packs up extremely small. And when the weather turns, or you start your long descent, you'll be glad you have it on board.